55911921 has 16 divisors (see below), whose sum is σ = 82455744. Its totient is φ = 33476544.

The previous prime is 55911917. The next prime is 55911931. The reversal of 55911921 is 12911955.

It is a happy number.

It is not a de Polignac number, because 55911921 - 2² = 55911917 is a prime.

It is a super-2 number, since 2×55911921² = 6252285819820482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (55911901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17931 + ... + 20816.

It is an arithmetic number, because the mean of its divisors is an integer number (5153484).

Almost surely, 2^55911921 is an apocalyptic number.

It is an amenable number.

55911921 is a deficient number, since it is larger than the sum of its proper divisors (26543823).

55911921 is a wasteful number, since it uses less digits than its factorization.

55911921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38800.

The product of its digits is 4050, while the sum is 33.

The square root of 55911921 is about 7477.4274319448. The cubic root of 55911921 is about 382.3855490803.

The spelling of 55911921 in words is "fifty-five million, nine hundred eleven thousand, nine hundred twenty-one".