721646120 has 32 divisors (see below), whose sum is σ = 1748605320. Its totient is φ = 266453760.

The previous prime is 721646083. The next prime is 721646129. The reversal of 721646120 is 21646127.

It can be written as a sum of positive squares in 4 ways, for example, as 227828836 + 493817284 = 15094^2 + 22222^2 .

It is a super-2 number, since 2×721646120² = 1041546245022108800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (721646129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 693371 + ... + 694410.

Almost surely, 2^721646120 is an apocalyptic number.

It is an amenable number.

721646120 is an abundant number, since it is smaller than the sum of its proper divisors (1026959200).

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

721646120 is a wasteful number, since it uses less digits than its factorization.

721646120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1387805 (or 1387801 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 721646120 is about 26863.4718530573. The cubic root of 721646120 is about 896.9634784973.

The spelling of 721646120 in words is "seven hundred twenty-one million, six hundred forty-six thousand, one hundred twenty".