51664807 has 4 divisors (see below), whose sum is σ = 51679480. Its totient is φ = 51650136.

The previous prime is 51664799. The next prime is 51664813. The reversal of 51664807 is 70846615.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a 3-Lehmer number, since φ(51664807) divides (51664807-1)³.

It is a cyclic number.

It is not a de Polignac number, because 51664807 - 2³ = 51664799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51667807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1468 + ... + 10270.

It is an arithmetic number, because the mean of its divisors is an integer number (12919870).

Almost surely, 2^51664807 is an apocalyptic number.

51664807 is the 5869-th pentagonal number.

51664807 is a deficient number, since it is larger than the sum of its proper divisors (14673).

51664807 is an equidigital number, since it uses as much as digits as its factorization.

51664807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14672.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 51664807 is about 7187.8235231536. The cubic root of 51664807 is about 372.4473916366.

The spelling of 51664807 in words is "fifty-one million, six hundred sixty-four thousand, eight hundred seven".