51042491 has 2 divisors, whose sum is σ = 51042492. Its totient is φ = 51042490.

The previous prime is 51042487. The next prime is 51042521. The reversal of 51042491 is 19424015.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51042491 - 2² = 51042487 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51042491.

It is not a weakly prime, because it can be changed into another prime (51042191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25521245 + 25521246.

It is an arithmetic number, because the mean of its divisors is an integer number (25521246).

Almost surely, 2^51042491 is an apocalyptic number.

51042491 is a deficient number, since it is larger than the sum of its proper divisors (1).

51042491 is an equidigital number, since it uses as much as digits as its factorization.

51042491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 51042491 is about 7144.4027742002. The cubic root of 51042491 is about 370.9459384613.

The spelling of 51042491 in words is "fifty-one million, forty-two thousand, four hundred ninety-one".