51791618 has 4 divisors (see below), whose sum is σ = 77687430. Its totient is φ = 25895808.

The previous prime is 51791611. The next prime is 51791627. The reversal of 51791618 is 81619715.

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

It can be written as a sum of positive squares in only one way, i.e., 32982049 + 18809569 = 5743^2 + 4337^2 .

It is not an unprimeable number, because it can be changed into a prime (51791611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12947903 + ... + 12947906.

Almost surely, 2^51791618 is an apocalyptic number.

51791618 is a deficient number, since it is larger than the sum of its proper divisors (25895812).

51791618 is a wasteful number, since it uses less digits than its factorization.

51791618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25895811.

The product of its digits is 15120, while the sum is 38.

The square root of 51791618 is about 7196.6393545877. The cubic root of 51791618 is about 372.7518660570.

The spelling of 51791618 in words is "fifty-one million, seven hundred ninety-one thousand, six hundred eighteen".