721723356 has 18 divisors (see below), whose sum is σ = 1824356352. Its totient is φ = 240574440.

The previous prime is 721723349. The next prime is 721723361. The reversal of 721723356 is 653327127.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 20047871 = 721723356 / (7 + 2 + 1 + 7 + 2 + 3 + 3 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 721723356.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10023900 + ... + 10023971.

Almost surely, 2^721723356 is an apocalyptic number.

It is an amenable number.

721723356 is an abundant number, since it is smaller than the sum of its proper divisors (1102632996).

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

721723356 is a wasteful number, since it uses less digits than its factorization.

721723356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20047881 (or 20047876 counting only the distinct ones).

The product of its digits is 52920, while the sum is 36.

The square root of 721723356 is about 26864.9093800817. The cubic root of 721723356 is about 896.9954772836.

The spelling of 721723356 in words is "seven hundred twenty-one million, seven hundred twenty-three thousand, three hundred fifty-six".