390228821 has 4 divisors (see below), whose sum is σ = 410767200. Its totient is φ = 369690444.

The previous prime is 390228803. The next prime is 390228869. The reversal of 390228821 is 128822093.

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.

It is a cyclic number.

It is not a de Polignac number, because 390228821 - 2⁶ = 390228757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390228871) 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, 10269161 + ... + 10269198.

It is an arithmetic number, because the mean of its divisors is an integer number (102691800).

Almost surely, 2^390228821 is an apocalyptic number.

It is an amenable number.

390228821 is a deficient number, since it is larger than the sum of its proper divisors (20538379).

390228821 is a wasteful number, since it uses less digits than its factorization.

390228821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20538378.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 390228821 is about 19754.2102094718. The cubic root of 390228821 is about 730.7572182803.

It can be divided in two parts, 3902 and 28821, that added together give a palindrome (32723).

The spelling of 390228821 in words is "three hundred ninety million, two hundred twenty-eight thousand, eight hundred twenty-one".