55139815 has 4 divisors (see below), whose sum is σ = 66167784. Its totient is φ = 44111848.

The previous prime is 55139801. The next prime is 55139831. The reversal of 55139815 is 51893155.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 55139815 - 2⁵ = 55139783 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 5513977 + ... + 5513986.

It is an arithmetic number, because the mean of its divisors is an integer number (16541946).

Almost surely, 2^55139815 is an apocalyptic number.

55139815 is a deficient number, since it is larger than the sum of its proper divisors (11027969).

55139815 is a wasteful number, since it uses less digits than its factorization.

55139815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11027968.

The product of its digits is 27000, while the sum is 37.

The square root of 55139815 is about 7425.6188294310. The cubic root of 55139815 is about 380.6172217622.

The spelling of 55139815 in words is "fifty-five million, one hundred thirty-nine thousand, eight hundred fifteen".