390821421 has 8 divisors (see below), whose sum is σ = 521401504. Its totient is φ = 260394480.

The previous prime is 390821411. The next prime is 390821437. The reversal of 390821421 is 124128093.

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

It is not a de Polignac number, because 390821421 - 2⁶ = 390821357 is a prime.

It is a super-2 number, since 2×390821421² = 305482766224918482, 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 (390821411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32191 + ... + 42636.

It is an arithmetic number, because the mean of its divisors is an integer number (65175188).

Almost surely, 2^390821421 is an apocalyptic number.

It is an amenable number.

390821421 is a deficient number, since it is larger than the sum of its proper divisors (130580083).

390821421 is a wasteful number, since it uses less digits than its factorization.

390821421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76571.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 390821421 is about 19769.2038534687. The cubic root of 390821421 is about 731.1269395663.

The spelling of 390821421 in words is "three hundred ninety million, eight hundred twenty-one thousand, four hundred twenty-one".