642516451 has 2 divisors, whose sum is σ = 642516452. Its totient is φ = 642516450.

The previous prime is 642516439. The next prime is 642516467. The reversal of 642516451 is 154615246.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642516451 is a prime.

It is not a weakly prime, because it can be changed into another prime (642516421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321258225 + 321258226.

It is an arithmetic number, because the mean of its divisors is an integer number (321258226).

Almost surely, 2^642516451 is an apocalyptic number.

642516451 is a deficient number, since it is larger than the sum of its proper divisors (1).

642516451 is an equidigital number, since it uses as much as digits as its factorization.

642516451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28800, while the sum is 34.

The square root of 642516451 is about 25347.9082174447. The cubic root of 642516451 is about 862.9018841535.

The spelling of 642516451 in words is "six hundred forty-two million, five hundred sixteen thousand, four hundred fifty-one".