2157649920 has 224 divisors, whose sum is σ = 7675107840. Its totient is φ = 575078400.

The previous prime is 2157649903. The next prime is 2157649927. The reversal of 2157649920 is 299467512.

2157649920 is a `hidden beast` number, since 2 + 157 + 6 + 499 + 2 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (2157649927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1104945 + ... + 1106895.

Almost surely, 2^2157649920 is an apocalyptic number.

2157649920 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 2157649920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3837553920).

2157649920 is an abundant number, since it is smaller than the sum of its proper divisors (5517457920).

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

2157649920 is an equidigital number, since it uses as much as digits as its factorization.

2157649920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1991 (or 1961 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The square root of 2157649920 is about 46450.5104385302. The cubic root of 2157649920 is about 1292.1918389078.

The spelling of 2157649920 in words is "two billion, one hundred fifty-seven million, six hundred forty-nine thousand, nine hundred twenty".