55155551 has 6 divisors (see below), whose sum is σ = 60625656. Its totient is φ = 50141300.

The previous prime is 55155547. The next prime is 55155553. The reversal of 55155551 is 15555155.

It is not a de Polignac number, because 55155551 - 2² = 55155547 is a prime.

It is a super-2 number, since 2×55155551² = 6084269612227202, which 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 (55155553) 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, 227795 + ... + 228036.

It is an arithmetic number, because the mean of its divisors is an integer number (10104276).

Almost surely, 2^55155551 is an apocalyptic number.

55155551 is a deficient number, since it is larger than the sum of its proper divisors (5470105).

55155551 is a wasteful number, since it uses less digits than its factorization.

55155551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455853 (or 455842 counting only the distinct ones).

The product of its digits is 15625, while the sum is 32.

The square root of 55155551 is about 7426.6783288358. The cubic root of 55155551 is about 380.6534256252.

The spelling of 55155551 in words is "fifty-five million, one hundred fifty-five thousand, five hundred fifty-one".