51165643 has 4 divisors (see below), whose sum is σ = 51232608. Its totient is φ = 51098680.

The previous prime is 51165619. The next prime is 51165659. The reversal of 51165643 is 34656115.

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 51165643 - 2²¹ = 49068491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51165943) 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, 32323 + ... + 33868.

It is an arithmetic number, because the mean of its divisors is an integer number (12808152).

Almost surely, 2^51165643 is an apocalyptic number.

51165643 is a deficient number, since it is larger than the sum of its proper divisors (66965).

51165643 is an equidigital number, since it uses as much as digits as its factorization.

51165643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66964.

The product of its digits is 10800, while the sum is 31.

The square root of 51165643 is about 7153.0163567547. The cubic root of 51165643 is about 371.2440302562.

The spelling of 51165643 in words is "fifty-one million, one hundred sixty-five thousand, six hundred forty-three".