51664765 has 8 divisors (see below), whose sum is σ = 63673560. Its totient is φ = 40214592.

The previous prime is 51664757. The next prime is 51664793. The reversal of 51664765 is 56746615.

It can be written as a sum of positive squares in 4 ways, for example, as 1792921 + 49871844 = 1339^2 + 7062^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51664765 - 2³ = 51664757 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139450 + ... + 139819.

It is an arithmetic number, because the mean of its divisors is an integer number (7959195).

Almost surely, 2^51664765 is an apocalyptic number.

It is an amenable number.

51664765 is a deficient number, since it is larger than the sum of its proper divisors (12008795).

51664765 is a wasteful number, since it uses less digits than its factorization.

51664765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279311.

The product of its digits is 151200, while the sum is 40.

The square root of 51664765 is about 7187.8206015454. The cubic root of 51664765 is about 372.4472907117.

The spelling of 51664765 in words is "fifty-one million, six hundred sixty-four thousand, seven hundred sixty-five".