921397 has 4 divisors (see below), whose sum is σ = 923436. Its totient is φ = 919360.

The previous prime is 921379. The next prime is 921407. The reversal of 921397 is 793129.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 617796 + 303601 = 786^2 + 551^2 .

It is a cyclic number.

It is not a de Polignac number, because 921397 - 2¹¹ = 919349 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

921397 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4 + ... + 1357.

It is an arithmetic number, because the mean of its divisors is an integer number (230859).

2⁹²¹³⁹⁷ is an apocalyptic number.

It is an amenable number.

921397 is a deficient number, since it is larger than the sum of its proper divisors (2039).

921397 is a wasteful number, since it uses less digits than its factorization.

921397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2038.

The product of its digits is 3402, while the sum is 31.

The square root of 921397 is about 959.8942650105. The cubic root of 921397 is about 97.3080862251.

The spelling of 921397 in words is "nine hundred twenty-one thousand, three hundred ninety-seven".