55691391 has 24 divisors (see below), whose sum is σ = 86671920. Its totient is φ = 31715712.

The previous prime is 55691369. The next prime is 55691453. The reversal of 55691391 is 19319655.

It is not a de Polignac number, because 55691391 - 2⁵ = 55691359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55691341) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66765 + ... + 67593.

It is an arithmetic number, because the mean of its divisors is an integer number (3611330).

Almost surely, 2^55691391 is an apocalyptic number.

55691391 is a deficient number, since it is larger than the sum of its proper divisors (30980529).

55691391 is a wasteful number, since it uses less digits than its factorization.

55691391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1303 (or 1296 counting only the distinct ones).

The product of its digits is 36450, while the sum is 39.

The square root of 55691391 is about 7462.6664805551. Note that the first 3 decimals coincide. The cubic root of 55691391 is about 381.8821466068.

The spelling of 55691391 in words is "fifty-five million, six hundred ninety-one thousand, three hundred ninety-one".