393917421 has 8 divisors (see below), whose sum is σ = 556118784. Its totient is φ = 247163840.

The previous prime is 393917401. The next prime is 393917431. The reversal of 393917421 is 124719393.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 393917421 - 2⁶ = 393917357 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 393917421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393917401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3861885 + ... + 3861986.

It is an arithmetic number, because the mean of its divisors is an integer number (69514848).

Almost surely, 2^393917421 is an apocalyptic number.

It is an amenable number.

393917421 is a deficient number, since it is larger than the sum of its proper divisors (162201363).

393917421 is a wasteful number, since it uses less digits than its factorization.

393917421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7723891.

The product of its digits is 40824, while the sum is 39.

The square root of 393917421 is about 19847.3529973143. The cubic root of 393917421 is about 733.0524720373.

The spelling of 393917421 in words is "three hundred ninety-three million, nine hundred seventeen thousand, four hundred twenty-one".