721369656 has 192 divisors, whose sum is σ = 2385676800. Its totient is φ = 192326400.

The previous prime is 721369651. The next prime is 721369657. The reversal of 721369656 is 656963127.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721369651) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 679366 + ... + 680426.

It is an arithmetic number, because the mean of its divisors is an integer number (12425400).

Almost surely, 2^721369656 is an apocalyptic number.

721369656 is a gapful number since it is divisible by the number (76) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721369656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1192838400).

721369656 is an abundant number, since it is smaller than the sum of its proper divisors (1664307144).

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

721369656 is a wasteful number, since it uses less digits than its factorization.

721369656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1170 (or 1163 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 721369656 is about 26858.3256365694. The cubic root of 721369656 is about 896.8489210626.

The spelling of 721369656 in words is "seven hundred twenty-one million, three hundred sixty-nine thousand, six hundred fifty-six".