390521401721 has 12 divisors (see below), whose sum is σ = 429414919332. Its totient is φ = 354883716000.

The previous prime is 390521401637. The next prime is 390521401733. The reversal of 390521401721 is 127104125093.

It can be written as a sum of positive squares in 2 ways, for example, as 285221151721 + 105300250000 = 534061^2 + 324500^2 .

It is not a de Polignac number, because 390521401721 - 2¹⁸ = 390521139577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (390521401421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 298550 + ... + 932831.

It is an arithmetic number, because the mean of its divisors is an integer number (35784576611).

Almost surely, 2^390521401721 is an apocalyptic number.

It is an amenable number.

390521401721 is a deficient number, since it is larger than the sum of its proper divisors (38893517611).

390521401721 is a wasteful number, since it uses less digits than its factorization.

390521401721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1234024 (or 1234013 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The spelling of 390521401721 in words is "three hundred ninety billion, five hundred twenty-one million, four hundred one thousand, seven hundred twenty-one".