721664430 has 32 divisors (see below), whose sum is σ = 1764677664. Its totient is φ = 188812416.

The previous prime is 721664429. The next prime is 721664431. The reversal of 721664430 is 34466127.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (721664429) and next prime (721664431).

It is a junction number, because it is equal to n+sod(n) for n = 721664391 and 721664400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721664431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 225349 + ... + 228528.

It is an arithmetic number, because the mean of its divisors is an integer number (55146177).

Almost surely, 2^721664430 is an apocalyptic number.

721664430 is an abundant number, since it is smaller than the sum of its proper divisors (1043013234).

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

721664430 is a wasteful number, since it uses less digits than its factorization.

721664430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453940.

The product of its (nonzero) digits is 24192, while the sum is 33.

The square root of 721664430 is about 26863.8126482449. The cubic root of 721664430 is about 896.9710645158.

The spelling of 721664430 in words is "seven hundred twenty-one million, six hundred sixty-four thousand, four hundred thirty".