921399 has 8 divisors (see below), whose sum is σ = 1234032. Its totient is φ = 611520.

The previous prime is 921379. The next prime is 921407. The reversal of 921399 is 993129.

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

It is not a de Polignac number, because 921399 - 2⁸ = 921143 is a prime.

It is a super-2 number, since 2×921399² = 1697952234402, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 921399.

It is not an unprimeable number, because it can be changed into a prime (921379) 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, 297 + ... + 1389.

It is an arithmetic number, because the mean of its divisors is an integer number (154254).

2⁹²¹³⁹⁹ is an apocalyptic number.

921399 is a deficient number, since it is larger than the sum of its proper divisors (312633).

921399 is a wasteful number, since it uses less digits than its factorization.

921399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1377.

The product of its digits is 4374, while the sum is 33.

The square root of 921399 is about 959.8953067913. The cubic root of 921399 is about 97.3081566312.

The spelling of 921399 in words is "nine hundred twenty-one thousand, three hundred ninety-nine".