390560721 has 4 divisors (see below), whose sum is σ = 520747632. Its totient is φ = 260373812.

The previous prime is 390560683. The next prime is 390560743. The reversal of 390560721 is 127065093.

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, and also an emirpimes, since its reverse is a distinct semiprime: 127065093 = 3 ⋅42355031.

It is a cyclic number.

It is not a de Polignac number, because 390560721 - 2¹⁸ = 390298577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (390560791) 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, 65093451 + ... + 65093456.

It is an arithmetic number, because the mean of its divisors is an integer number (130186908).

Almost surely, 2^390560721 is an apocalyptic number.

It is an amenable number.

390560721 is a deficient number, since it is larger than the sum of its proper divisors (130186911).

390560721 is a wasteful number, since it uses less digits than its factorization.

390560721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130186910.

The product of its (nonzero) digits is 11340, while the sum is 33.

The square root of 390560721 is about 19762.6091647839. The cubic root of 390560721 is about 730.9643357273.

The spelling of 390560721 in words is "three hundred ninety million, five hundred sixty thousand, seven hundred twenty-one".