721311213 has 24 divisors (see below), whose sum is σ = 1135481952. Its totient is φ = 406020384.

The previous prime is 721311191. The next prime is 721311233. The reversal of 721311213 is 312113127.

It is a happy number.

It is not a de Polignac number, because 721311213 - 2⁹ = 721310701 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 721311213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721311233) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26770 + ... + 46467.

It is an arithmetic number, because the mean of its divisors is an integer number (47311748).

Almost surely, 2^721311213 is an apocalyptic number.

It is an amenable number.

721311213 is a deficient number, since it is larger than the sum of its proper divisors (414170739).

721311213 is a wasteful number, since it uses less digits than its factorization.

721311213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73321 (or 73314 counting only the distinct ones).

The product of its digits is 252, while the sum is 21.

The square root of 721311213 is about 26857.2376278723. The cubic root of 721311213 is about 896.8247004906.

The spelling of 721311213 in words is "seven hundred twenty-one million, three hundred eleven thousand, two hundred thirteen".