393408910021 has 4 divisors (see below), whose sum is σ = 393414196032. Its totient is φ = 393403624012.

The previous prime is 393408910009. The next prime is 393408910039. The reversal of 393408910021 is 120019804393.

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 393408910021 - 2⁷ = 393408909893 is a prime.

It is a super-2 number, since 2×393408910021² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393408910621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2529751 + ... + 2680756.

It is an arithmetic number, because the mean of its divisors is an integer number (98353549008).

Almost surely, 2^393408910021 is an apocalyptic number.

It is an amenable number.

393408910021 is a deficient number, since it is larger than the sum of its proper divisors (5286011).

393408910021 is an equidigital number, since it uses as much as digits as its factorization.

393408910021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5286010.

The product of its (nonzero) digits is 46656, while the sum is 40.

The spelling of 393408910021 in words is "three hundred ninety-three billion, four hundred eight million, nine hundred ten thousand, twenty-one".