2157664320 has 672 divisors, whose sum is σ = 9205447680. Its totient is φ = 452874240.

The previous prime is 2157664307. The next prime is 2157664321. The reversal of 2157664320 is 234667512.

2157664320 is a `hidden beast` number, since 2 + 1 + 5 + 7 + 6 + 643 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

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

It is not an unprimeable number, because it can be changed into a prime (2157664321) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 16470655 + ... + 16470785.

Almost surely, 2^2157664320 is an apocalyptic number.

2157664320 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 2157664320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4602723840).

2157664320 is an abundant number, since it is smaller than the sum of its proper divisors (7047783360).

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

2157664320 is a wasteful number, since it uses less digits than its factorization.

2157664320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 2157664320 is about 46450.6654419503. The cubic root of 2157664320 is about 1292.1947135665.

The spelling of 2157664320 in words is "two billion, one hundred fifty-seven million, six hundred sixty-four thousand, three hundred twenty".