2660991820 has 12 divisors (see below), whose sum is σ = 5588082864. Its totient is φ = 1064396720.

The previous prime is 2660991791. The next prime is 2660991841. The reversal of 2660991820 is 281990662.

2660991820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×2660991820² = 14161754932213824800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66524776 + ... + 66524815.

It is an arithmetic number, because the mean of its divisors is an integer number (465673572).

Almost surely, 2^2660991820 is an apocalyptic number.

2660991820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2660991820 is an abundant number, since it is smaller than the sum of its proper divisors (2927091044).

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

2660991820 is a wasteful number, since it uses less digits than its factorization.

2660991820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133049600 (or 133049598 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 2660991820 is about 51584.8022192583. The cubic root of 2660991820 is about 1385.7381703671.

The spelling of 2660991820 in words is "two billion, six hundred sixty million, nine hundred ninety-one thousand, eight hundred twenty".