51556665 has 16 divisors (see below), whose sum is σ = 87343488. Its totient is φ = 25879296.

The previous prime is 51556663. The next prime is 51556667. The reversal of 51556665 is 56665515.

It is an interprime number because it is at equal distance from previous prime (51556663) and next prime (51556667).

It is not a de Polignac number, because 51556665 - 2¹ = 51556663 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51556663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100837 + ... + 101346.

It is an arithmetic number, because the mean of its divisors is an integer number (5458968).

Almost surely, 2^51556665 is an apocalyptic number.

It is an amenable number.

51556665 is a deficient number, since it is larger than the sum of its proper divisors (35786823).

51556665 is a wasteful number, since it uses less digits than its factorization.

51556665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202208.

The product of its digits is 135000, while the sum is 39.

The square root of 51556665 is about 7180.2969994284. The cubic root of 51556665 is about 372.1873478213.

The spelling of 51556665 in words is "fifty-one million, five hundred fifty-six thousand, six hundred sixty-five".