721621407 has 16 divisors (see below), whose sum is σ = 1038901248. Its totient is φ = 442906080.

The previous prime is 721621393. The next prime is 721621421. The reversal of 721621407 is 704126127.

It is an interprime number because it is at equal distance from previous prime (721621393) and next prime (721621421).

It is not a de Polignac number, because 721621407 - 2⁴ = 721621391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721621427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9219 + ... + 39092.

It is an arithmetic number, because the mean of its divisors is an integer number (64931328).

Almost surely, 2^721621407 is an apocalyptic number.

721621407 is a deficient number, since it is larger than the sum of its proper divisors (317279841).

721621407 is a wasteful number, since it uses less digits than its factorization.

721621407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48710.

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 721621407 is about 26863.0118750672. The cubic root of 721621407 is about 896.9532394476.

The spelling of 721621407 in words is "seven hundred twenty-one million, six hundred twenty-one thousand, four hundred seven".