51661657 has 16 divisors (see below), whose sum is σ = 58637952. Its totient is φ = 45239040.

The previous prime is 51661651. The next prime is 51661667. The reversal of 51661657 is 75616615.

It is not a de Polignac number, because 51661657 - 2⁷ = 51661529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51661651) 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, 12682 + ... + 16252.

It is an arithmetic number, because the mean of its divisors is an integer number (3664872).

Almost surely, 2^51661657 is an apocalyptic number.

It is an amenable number.

51661657 is a deficient number, since it is larger than the sum of its proper divisors (6976295).

51661657 is a wasteful number, since it uses less digits than its factorization.

51661657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3648.

The product of its digits is 37800, while the sum is 37.

The square root of 51661657 is about 7187.6043992418. The cubic root of 51661657 is about 372.4398221181.

The spelling of 51661657 in words is "fifty-one million, six hundred sixty-one thousand, six hundred fifty-seven".