55400391 has 6 divisors (see below), whose sum is σ = 80022800. Its totient is φ = 36933588.

The previous prime is 55400369. The next prime is 55400407. The reversal of 55400391 is 19300455.

It is not a de Polignac number, because 55400391 - 2⁶ = 55400327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55400311) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3077791 + ... + 3077808.

Almost surely, 2^55400391 is an apocalyptic number.

55400391 is a deficient number, since it is larger than the sum of its proper divisors (24622409).

55400391 is a wasteful number, since it uses less digits than its factorization.

55400391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6155605 (or 6155602 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 27.

The square root of 55400391 is about 7443.1438922004. The cubic root of 55400391 is about 381.2158447947.

The spelling of 55400391 in words is "fifty-five million, four hundred thousand, three hundred ninety-one".