399622821 has 16 divisors (see below), whose sum is σ = 575703744. Its totient is φ = 245113344.

The previous prime is 399622819. The next prime is 399622849. The reversal of 399622821 is 128226993.

It is not a de Polignac number, because 399622821 - 2¹ = 399622819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399622721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4716 + ... + 28661.

It is an arithmetic number, because the mean of its divisors is an integer number (35981484).

Almost surely, 2^399622821 is an apocalyptic number.

It is an amenable number.

399622821 is a deficient number, since it is larger than the sum of its proper divisors (176080923).

399622821 is a wasteful number, since it uses less digits than its factorization.

399622821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33700.

The product of its digits is 93312, while the sum is 42.

The square root of 399622821 is about 19990.5683010764. The cubic root of 399622821 is about 736.5746370114.

The spelling of 399622821 in words is "three hundred ninety-nine million, six hundred twenty-two thousand, eight hundred twenty-one".