721670556 has 12 divisors (see below), whose sum is σ = 1683897992. Its totient is φ = 240556848.

The previous prime is 721670549. The next prime is 721670557. The reversal of 721670556 is 655076127.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721670557) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30069595 + ... + 30069618.

Almost surely, 2^721670556 is an apocalyptic number.

It is an amenable number.

721670556 is an abundant number, since it is smaller than the sum of its proper divisors (962227436).

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

721670556 is a wasteful number, since it uses less digits than its factorization.

721670556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60139220 (or 60139218 counting only the distinct ones).

The product of its (nonzero) digits is 88200, while the sum is 39.

The square root of 721670556 is about 26863.9266675592. The cubic root of 721670556 is about 896.9736025510.

The spelling of 721670556 in words is "seven hundred twenty-one million, six hundred seventy thousand, five hundred fifty-six".