55188151981 has 4 divisors (see below), whose sum is σ = 55211313472. Its totient is φ = 55164990492.

The previous prime is 55188151973. The next prime is 55188152009. The reversal of 55188151981 is 18915188155.

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.

It is a cyclic number.

It is not a de Polignac number, because 55188151981 - 2³ = 55188151973 is a prime.

It is a super-2 number, since 2×55188151981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55188151961) 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, 11577171 + ... + 11581936.

It is an arithmetic number, because the mean of its divisors is an integer number (13802828368).

Almost surely, 2^55188151981 is an apocalyptic number.

It is an amenable number.

55188151981 is a deficient number, since it is larger than the sum of its proper divisors (23161491).

55188151981 is a wasteful number, since it uses less digits than its factorization.

55188151981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23161490.

The product of its digits is 576000, while the sum is 52.

The spelling of 55188151981 in words is "fifty-five billion, one hundred eighty-eight million, one hundred fifty-one thousand, nine hundred eighty-one".