51664747 has 4 divisors (see below), whose sum is σ = 53446320. Its totient is φ = 49883176.

The previous prime is 51664733. The next prime is 51664757. The reversal of 51664747 is 74746615.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51664747 - 2⁷ = 51664619 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51664757) 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, 890743 + ... + 890800.

It is an arithmetic number, because the mean of its divisors is an integer number (13361580).

Almost surely, 2^51664747 is an apocalyptic number.

51664747 is a deficient number, since it is larger than the sum of its proper divisors (1781573).

51664747 is a wasteful number, since it uses less digits than its factorization.

51664747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781572.

The product of its digits is 141120, while the sum is 40.

The square root of 51664747 is about 7187.8193494272. The cubic root of 51664747 is about 372.4472474581.

The spelling of 51664747 in words is "fifty-one million, six hundred sixty-four thousand, seven hundred forty-seven".