51665730 has 16 divisors (see below), whose sum is σ = 123997824. Its totient is φ = 13777520.

The previous prime is 51665723. The next prime is 51665741. The reversal of 51665730 is 3756615.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 51665691 and 51665700.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 861066 + ... + 861125.

It is an arithmetic number, because the mean of its divisors is an integer number (7749864).

Almost surely, 2^51665730 is an apocalyptic number.

51665730 is an abundant number, since it is smaller than the sum of its proper divisors (72332094).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51665730 is a wasteful number, since it uses less digits than its factorization.

51665730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1722201.

The product of its (nonzero) digits is 18900, while the sum is 33.

The square root of 51665730 is about 7187.8877286725. The cubic root of 51665730 is about 372.4496095673.

The spelling of 51665730 in words is "fifty-one million, six hundred sixty-five thousand, seven hundred thirty".