396000721 has 4 divisors (see below), whose sum is σ = 396083200. Its totient is φ = 395918244.

The previous prime is 396000623. The next prime is 396000739. The reversal of 396000721 is 127000693.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 396000721 - 2¹³ = 395992529 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 396000721.

It is not an unprimeable number, because it can be changed into a prime (396003721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33561 + ... + 43798.

It is an arithmetic number, because the mean of its divisors is an integer number (99020800).

Almost surely, 2^396000721 is an apocalyptic number.

It is an amenable number.

396000721 is a deficient number, since it is larger than the sum of its proper divisors (82479).

396000721 is an equidigital number, since it uses as much as digits as its factorization.

396000721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82478.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 396000721 is about 19899.7668579308. The cubic root of 396000721 is about 734.3424918786.

Subtracting from 396000721 its sum of digits (28), we obtain a palindrome (396000693).

The spelling of 396000721 in words is "three hundred ninety-six million, seven hundred twenty-one", and thus it is an aban number.