55915551 has 6 divisors (see below), whose sum is σ = 80766920. Its totient is φ = 37277028.

The previous prime is 55915549. The next prime is 55915577. The reversal of 55915551 is 15551955.

It is a happy number.

55915551 is a `hidden beast` number, since 559 + 1 + 55 + 51 = 666.

It is not a de Polignac number, because 55915551 - 2¹ = 55915549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55915501) 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, 3106411 + ... + 3106428.

Almost surely, 2^55915551 is an apocalyptic number.

55915551 is a deficient number, since it is larger than the sum of its proper divisors (24851369).

55915551 is a wasteful number, since it uses less digits than its factorization.

55915551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6212845 (or 6212842 counting only the distinct ones).

The product of its digits is 28125, while the sum is 36.

The square root of 55915551 is about 7477.6701585454. The cubic root of 55915551 is about 382.3938241761.

It can be divided in two parts, 559 and 15551, that added together give a triangular number (16110 = T₁₇₉).

The spelling of 55915551 in words is "fifty-five million, nine hundred fifteen thousand, five hundred fifty-one".