2181263616 has 243 divisors, whose sum is σ = 7368927111. Its totient is φ = 618734592.

The previous prime is 2181263603. The next prime is 2181263629. The reversal of 2181263616 is 6163621812.

It is a happy number.

The square root of 2181263616 is 46704.

It is a perfect power (a square), and thus also a powerful number.

2181263616 is a `hidden beast` number, since 2 + 1 + 8 + 1 + 2 + 636 + 16 = 666.

2181263616 is nontrivially palindromic in base 5.

It is an interprime number because it is at equal distance from previous prime (2181263603) and next prime (2181263629).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 15692475 + ... + 15692613.

Almost surely, 2^2181263616 is an apocalyptic number.

2181263616 is the 46704-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2181263616

2181263616 is an abundant number, since it is smaller than the sum of its proper divisors (5187663495).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2181263616 is an equidigital number, since it uses as much as digits as its factorization.

2181263616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314 (or 151 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The cubic root of 2181263616 is about 1296.8887365427. Note that the first 3 decimals are identical.

Multiplying 2181263616 by its sum of digits (36), we get a square (78525490176 = 280224²).

2181263616 divided by its sum of digits (36) gives a square (60590656 = 7784²).

Multiplying 2181263616 by its product of digits (20736), we get a square (45230682341376 = 6725376²).

The spelling of 2181263616 in words is "two billion, one hundred eighty-one million, two hundred sixty-three thousand, six hundred sixteen".