721642404020 has 12 divisors (see below), whose sum is σ = 1515449048484. Its totient is φ = 288656961600.

The previous prime is 721642404017. The next prime is 721642404139. The reversal of 721642404020 is 20404246127.

It can be written as a sum of positive squares in 2 ways, for example, as 206939468836 + 514702935184 = 454906^2 + 717428^2 .

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18041060081 + ... + 18041060120.

It is an arithmetic number, because the mean of its divisors is an integer number (126287420707).

Almost surely, 2^721642404020 is an apocalyptic number.

It is an amenable number.

721642404020 is an abundant number, since it is smaller than the sum of its proper divisors (793806644464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721642404020 is a wasteful number, since it uses less digits than its factorization.

721642404020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36082120210 (or 36082120208 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 32.

The spelling of 721642404020 in words is "seven hundred twenty-one billion, six hundred forty-two million, four hundred four thousand, twenty".