55111520521 has 4 divisors (see below), whose sum is σ = 56284106112. Its totient is φ = 53938934932.

The previous prime is 55111520393. The next prime is 55111520531. The reversal of 55111520521 is 12502511155.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12502511155 = 5 ⋅2500502231.

It is a cyclic number.

It is not a de Polignac number, because 55111520521 - 2⁷ = 55111520393 is a prime.

It is a super-2 number, since 2×55111520521² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55111520521.

It is not an unprimeable number, because it can be changed into a prime (55111520531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 586292725 + ... + 586292818.

It is an arithmetic number, because the mean of its divisors is an integer number (14071026528).

Almost surely, 2^55111520521 is an apocalyptic number.

It is an amenable number.

55111520521 is a deficient number, since it is larger than the sum of its proper divisors (1172585591).

55111520521 is a wasteful number, since it uses less digits than its factorization.

55111520521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172585590.

The product of its (nonzero) digits is 2500, while the sum is 28.

The spelling of 55111520521 in words is "fifty-five billion, one hundred eleven million, five hundred twenty thousand, five hundred twenty-one".