2196638640 has 720 divisors, whose sum is σ = 9427298400. Its totient is φ = 455196672.

The previous prime is 2196638627. The next prime is 2196638651. The reversal of 2196638640 is 468366912.

2196638640 is a `hidden beast` number, since 2 + 1 + 9 + 6 + 638 + 6 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 19439224 + ... + 19439336.

It is an arithmetic number, because the mean of its divisors is an integer number (13093470).

Almost surely, 2^2196638640 is an apocalyptic number.

2196638640 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 2196638640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4713649200).

2196638640 is an abundant number, since it is smaller than the sum of its proper divisors (7230659760).

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

2196638640 is a wasteful number, since it uses less digits than its factorization.

2196638640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 2196638640 is about 46868.3116828417. The cubic root of 2196638640 is about 1299.9287219302.

It can be divided in two parts, 21966 and 38640, that added together give a palindrome (60606).

The spelling of 2196638640 in words is "two billion, one hundred ninety-six million, six hundred thirty-eight thousand, six hundred forty".