2157800820 has 96 divisors (see below), whose sum is σ = 7311161088. Its totient is φ = 464197632.

The previous prime is 2157800783. The next prime is 2157800863. The reversal of 2157800820 is 280087512.

It is a super-2 number, since 2×2157800820² = 9312208757585344800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 143967 + ... + 158246.

It is an arithmetic number, because the mean of its divisors is an integer number (76157928).

Almost surely, 2^2157800820 is an apocalyptic number.

2157800820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2157800820 is an abundant number, since it is smaller than the sum of its proper divisors (5153360268).

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

2157800820 is a wasteful number, since it uses less digits than its factorization.

2157800820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302249 (or 302247 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 2157800820 is about 46452.1347195153. The cubic root of 2157800820 is about 1292.2219622998.

The spelling of 2157800820 in words is "two billion, one hundred fifty-seven million, eight hundred thousand, eight hundred twenty".