721620404 has 6 divisors (see below), whose sum is σ = 1262835714. Its totient is φ = 360810200.

The previous prime is 721620379. The next prime is 721620433. The reversal of 721620404 is 404026127.

It can be written as a sum of positive squares in only one way, i.e., 683822500 + 37797904 = 26150^2 + 6148^2 .

It is a congruent number.

It is an unprimeable number.

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, 90202547 + ... + 90202554.

It is an arithmetic number, because the mean of its divisors is an integer number (210472619).

Almost surely, 2^721620404 is an apocalyptic number.

It is an amenable number.

721620404 is a deficient number, since it is larger than the sum of its proper divisors (541215310).

721620404 is a wasteful number, since it uses less digits than its factorization.

721620404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180405105 (or 180405103 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 721620404 is about 26862.9932062680. The cubic root of 721620404 is about 896.9528238814.

The spelling of 721620404 in words is "seven hundred twenty-one million, six hundred twenty thousand, four hundred four".