55091720 has 16 divisors (see below), whose sum is σ = 123956460. Its totient is φ = 22036672.

The previous prime is 55091689. The next prime is 55091737. The reversal of 55091720 is 2719055.

It can be written as a sum of positive squares in 2 ways, for example, as 53787556 + 1304164 = 7334^2 + 1142^2 .

It is a super-2 number, since 2×55091720² = 6070195225116800, 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, 688607 + ... + 688686.

Almost surely, 2^55091720 is an apocalyptic number.

It is an amenable number.

55091720 is an abundant number, since it is smaller than the sum of its proper divisors (68864740).

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

55091720 is a wasteful number, since it uses less digits than its factorization.

55091720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1377304 (or 1377300 counting only the distinct ones).

The product of its (nonzero) digits is 3150, while the sum is 29.

The square root of 55091720 is about 7422.3796723153. The cubic root of 55091720 is about 380.5065267336.

The spelling of 55091720 in words is "fifty-five million, ninety-one thousand, seven hundred twenty".