721668770440 has 32 divisors (see below), whose sum is σ = 1624829492160. Its totient is φ = 288476440000.

The previous prime is 721668770413. The next prime is 721668770453. The reversal of 721668770440 is 44077866127.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5909686 + ... + 6030565.

It is an arithmetic number, because the mean of its divisors is an integer number (50775921630).

Almost surely, 2^721668770440 is an apocalyptic number.

It is an amenable number.

721668770440 is an abundant number, since it is smaller than the sum of its proper divisors (903160721720).

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

721668770440 is a wasteful number, since it uses less digits than its factorization.

721668770440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11941773 (or 11941769 counting only the distinct ones).

The product of its (nonzero) digits is 3161088, while the sum is 52.

The spelling of 721668770440 in words is "seven hundred twenty-one billion, six hundred sixty-eight million, seven hundred seventy thousand, four hundred forty".