393949521 has 16 divisors (see below), whose sum is σ = 667004800. Its totient is φ = 225113904.

The previous prime is 393949513. The next prime is 393949547. The reversal of 393949521 is 125949393.

393949521 is a `hidden beast` number, since 39 + 3 + 94 + 9 + 521 = 666.

It is not a de Polignac number, because 393949521 - 2³ = 393949513 is a prime.

It is a super-2 number, since 2×393949521² = 310392450192258882, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (393949561) 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, 1042006 + ... + 1042383.

It is an arithmetic number, because the mean of its divisors is an integer number (41687800).

Almost surely, 2^393949521 is an apocalyptic number.

It is an amenable number.

393949521 is a deficient number, since it is larger than the sum of its proper divisors (273055279).

393949521 is a wasteful number, since it uses less digits than its factorization.

393949521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2084405 (or 2084399 counting only the distinct ones).

The product of its digits is 262440, while the sum is 45.

The square root of 393949521 is about 19848.1616529088. The cubic root of 393949521 is about 733.0723834400.

The spelling of 393949521 in words is "three hundred ninety-three million, nine hundred forty-nine thousand, five hundred twenty-one".