390121021 has 8 divisors (see below), whose sum is σ = 403795800. Its totient is φ = 376461120.

The previous prime is 390121001. The next prime is 390121057. The reversal of 390121021 is 120121093.

It can be written as a sum of positive squares in 4 ways, for example, as 93799225 + 296321796 = 9685^2 + 17214^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 390121021 - 2⁵ = 390120989 is a prime.

It is a super-2 number, since 2×390121021² = 304388822052164882, which contains 22 as substring.

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 390121021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390121001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90135 + ... + 94363.

It is an arithmetic number, because the mean of its divisors is an integer number (50474475).

Almost surely, 2^390121021 is an apocalyptic number.

It is an amenable number.

390121021 is a deficient number, since it is larger than the sum of its proper divisors (13674779).

390121021 is a wasteful number, since it uses less digits than its factorization.

390121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7439.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 390121021 is about 19751.4814887390. The cubic root of 390121021 is about 730.6899219669.

The spelling of 390121021 in words is "three hundred ninety million, one hundred twenty-one thousand, twenty-one".