921381 has 8 divisors (see below), whose sum is σ = 1233120. Its totient is φ = 611952.

The previous prime is 921379. The next prime is 921407. The reversal of 921381 is 183129.

921381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 921381 - 2¹ = 921379 is a prime.

It is a super-2 number, since 2×921381² = 1697885894322, which contains 22 as substring.

921381 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921331) 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, 891 + ... + 1623.

It is an arithmetic number, because the mean of its divisors is an integer number (154140).

2⁹²¹³⁸¹ is an apocalyptic number.

It is an amenable number.

921381 is a deficient number, since it is larger than the sum of its proper divisors (311739).

921381 is a wasteful number, since it uses less digits than its factorization.

921381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1155.

The product of its digits is 432, while the sum is 24.

The square root of 921381 is about 959.8859307230. The cubic root of 921381 is about 97.3075229722.

The spelling of 921381 in words is "nine hundred twenty-one thousand, three hundred eighty-one".