51520665 has 32 divisors (see below), whose sum is σ = 96408576. Its totient is φ = 23002560.

The previous prime is 51520643. The next prime is 51520709. The reversal of 51520665 is 56602515.

It is not a de Polignac number, because 51520665 - 2¹¹ = 51518617 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1191 + ... + 10220.

It is an arithmetic number, because the mean of its divisors is an integer number (3012768).

Almost surely, 2^51520665 is an apocalyptic number.

It is an amenable number.

51520665 is a deficient number, since it is larger than the sum of its proper divisors (44887911).

51520665 is a wasteful number, since it uses less digits than its factorization.

51520665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11469.

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 51520665 is about 7177.7897015725. The cubic root of 51520665 is about 372.1006997010.

The spelling of 51520665 in words is "fifty-one million, five hundred twenty thousand, six hundred sixty-five".