51491551 has 2 divisors, whose sum is σ = 51491552. Its totient is φ = 51491550.

The previous prime is 51491533. The next prime is 51491563. The reversal of 51491551 is 15519415.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51491551 - 2¹⁹ = 50967263 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51491591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25745775 + 25745776.

It is an arithmetic number, because the mean of its divisors is an integer number (25745776).

Almost surely, 2^51491551 is an apocalyptic number.

51491551 is a deficient number, since it is larger than the sum of its proper divisors (1).

51491551 is an equidigital number, since it uses as much as digits as its factorization.

51491551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4500, while the sum is 31.

The square root of 51491551 is about 7175.7613533339. The cubic root of 51491551 is about 372.0305959149.

The spelling of 51491551 in words is "fifty-one million, four hundred ninety-one thousand, five hundred fifty-one".