721615451 has 2 divisors, whose sum is σ = 721615452. Its totient is φ = 721615450.

The previous prime is 721615441. The next prime is 721615463. The reversal of 721615451 is 154516127.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 721615451 - 2²² = 717421147 is a prime.

It is not a weakly prime, because it can be changed into another prime (721615441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360807725 + 360807726.

It is an arithmetic number, because the mean of its divisors is an integer number (360807726).

Almost surely, 2^721615451 is an apocalyptic number.

721615451 is a deficient number, since it is larger than the sum of its proper divisors (1).

721615451 is an equidigital number, since it uses as much as digits as its factorization.

721615451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8400, while the sum is 32.

The square root of 721615451 is about 26862.9010160854. The cubic root of 721615451 is about 896.9507717325.

The spelling of 721615451 in words is "seven hundred twenty-one million, six hundred fifteen thousand, four hundred fifty-one".