56511551 has 2 divisors, whose sum is σ = 56511552. Its totient is φ = 56511550.

The previous prime is 56511509. The next prime is 56511577. The reversal of 56511551 is 15511565.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 56511551 - 2⁶ = 56511487 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56511151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28255775 + 28255776.

It is an arithmetic number, because the mean of its divisors is an integer number (28255776).

Almost surely, 2^56511551 is an apocalyptic number.

56511551 is a deficient number, since it is larger than the sum of its proper divisors (1).

56511551 is an equidigital number, since it uses as much as digits as its factorization.

56511551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3750, while the sum is 29.

The square root of 56511551 is about 7517.4165110096. The cubic root of 56511551 is about 383.7476618177.

The spelling of 56511551 in words is "fifty-six million, five hundred eleven thousand, five hundred fifty-one".