392839921 has 2 divisors, whose sum is σ = 392839922. Its totient is φ = 392839920.

The previous prime is 392839919. The next prime is 392839949. The reversal of 392839921 is 129938293.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 347412321 + 45427600 = 18639^2 + 6740^2 .

It is a cyclic number.

It is not a de Polignac number, because 392839921 - 2¹ = 392839919 is a prime.

Together with 392839919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (392839981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196419960 + 196419961.

It is an arithmetic number, because the mean of its divisors is an integer number (196419961).

Almost surely, 2^392839921 is an apocalyptic number.

It is an amenable number.

392839921 is a deficient number, since it is larger than the sum of its proper divisors (1).

392839921 is an equidigital number, since it uses as much as digits as its factorization.

392839921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 46.

The square root of 392839921 is about 19820.1897316852. The cubic root of 392839921 is about 732.3834779145.

The spelling of 392839921 in words is "three hundred ninety-two million, eight hundred thirty-nine thousand, nine hundred twenty-one".