390418021 has 4 divisors (see below), whose sum is σ = 446192032. Its totient is φ = 334644012.

The previous prime is 390418019. The next prime is 390418033. The reversal of 390418021 is 120814093.

It is a happy number.

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: 120814093 = 1367 ⋅88379.

It is a cyclic number.

It is not a de Polignac number, because 390418021 - 2¹ = 390418019 is a prime.

It is a super-2 number, since 2×390418021² = 304852462243112882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390418001) 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, 27886995 + ... + 27887008.

It is an arithmetic number, because the mean of its divisors is an integer number (111548008).

Almost surely, 2^390418021 is an apocalyptic number.

It is an amenable number.

390418021 is a deficient number, since it is larger than the sum of its proper divisors (55774011).

390418021 is an equidigital number, since it uses as much as digits as its factorization.

390418021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55774010.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 390418021 is about 19758.9984817045. The cubic root of 390418021 is about 730.8753002188.

The spelling of 390418021 in words is "three hundred ninety million, four hundred eighteen thousand, twenty-one".