55645551 has 24 divisors (see below), whose sum is σ = 87076080. Its totient is φ = 34039296.

The previous prime is 55645549. The next prime is 55645571. The reversal of 55645551 is 15554655.

55645551 is a `hidden beast` number, since 5 + 5 + 645 + 5 + 5 + 1 = 666.

It is not a de Polignac number, because 55645551 - 2¹ = 55645549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55645501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19615 + ... + 22271.

It is an arithmetic number, because the mean of its divisors is an integer number (3628170).

Almost surely, 2^55645551 is an apocalyptic number.

55645551 is a deficient number, since it is larger than the sum of its proper divisors (31430529).

55645551 is a wasteful number, since it uses less digits than its factorization.

55645551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2855 (or 2852 counting only the distinct ones).

The product of its digits is 75000, while the sum is 36.

The square root of 55645551 is about 7459.5945600280. The cubic root of 55645551 is about 381.7773411635. Note that the first 3 decimals are identical.

The spelling of 55645551 in words is "fifty-five million, six hundred forty-five thousand, five hundred fifty-one".