2157213680 has 80 divisors (see below), whose sum is σ = 5172418944. Its totient is φ = 836209920.

The previous prime is 2157213671. The next prime is 2157213703. The reversal of 2157213680 is 863127512.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×2157213680² = 9307141722358284800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2157213680.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 448247 + ... + 453033.

Almost surely, 2^2157213680 is an apocalyptic number.

2157213680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2157213680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2586209472).

2157213680 is an abundant number, since it is smaller than the sum of its proper divisors (3015205264).

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

2157213680 is a wasteful number, since it uses less digits than its factorization.

2157213680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4974 (or 4968 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 2157213680 is about 46445.8144508200. The cubic root of 2157213680 is about 1292.1047466572.

The spelling of 2157213680 in words is "two billion, one hundred fifty-seven million, two hundred thirteen thousand, six hundred eighty".