721521936 has 60 divisors (see below), whose sum is σ = 2068526460. Its totient is φ = 234639360.

The previous prime is 721521923. The next prime is 721521949. The reversal of 721521936 is 639125127.

It is an interprime number because it is at equal distance from previous prime (721521923) and next prime (721521949).

It can be written as a sum of positive squares in 2 ways, for example, as 24561936 + 696960000 = 4956^2 + 26400^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 721521936.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55201 + ... + 67008.

It is an arithmetic number, because the mean of its divisors is an integer number (34475441).

Almost surely, 2^721521936 is an apocalyptic number.

It is an amenable number.

721521936 is an abundant number, since it is smaller than the sum of its proper divisors (1347004524).

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

721521936 is a wasteful number, since it uses less digits than its factorization.

721521936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122264 (or 122255 counting only the distinct ones).

The product of its digits is 22680, while the sum is 36.

The square root of 721521936 is about 26861.1603621288. The cubic root of 721521936 is about 896.9120244214.

It can be divided in two parts, 72152 and 1936, that added together give a cube (74088 = 42³).

The spelling of 721521936 in words is "seven hundred twenty-one million, five hundred twenty-one thousand, nine hundred thirty-six".