55400031 has 40 divisors (see below), whose sum is σ = 87398784. Its totient is φ = 34903440.

The previous prime is 55400027. The next prime is 55400041. The reversal of 55400031 is 13000455.

It is not a de Polignac number, because 55400031 - 2² = 55400027 is a prime.

It is a super-2 number, since 2×55400031² = 6138326869601922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 55399977 and 55400013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55400011) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 243940 + ... + 244166.

Almost surely, 2^55400031 is an apocalyptic number.

55400031 is a deficient number, since it is larger than the sum of its proper divisors (31998753).

55400031 is a wasteful number, since it uses less digits than its factorization.

55400031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 55400031 is about 7443.1197088318. The cubic root of 55400031 is about 381.2150190605.

Adding to 55400031 its reverse (13000455), we get a palindrome (68400486).

The spelling of 55400031 in words is "fifty-five million, four hundred thousand, thirty-one".