920991 has 8 divisors (see below), whose sum is σ = 1232560. Its totient is φ = 611712.

The previous prime is 920971. The next prime is 920999. The reversal of 920991 is 199029.

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

It is not a de Polignac number, because 920991 - 2⁷ = 920863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (920999) 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, 945 + ... + 1653.

It is an arithmetic number, because the mean of its divisors is an integer number (154070).

2⁹²⁰⁹⁹¹ is an apocalyptic number.

920991 is a deficient number, since it is larger than the sum of its proper divisors (311569).

920991 is a wasteful number, since it uses less digits than its factorization.

920991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1145.

The product of its (nonzero) digits is 1458, while the sum is 30.

The square root of 920991 is about 959.6827600827. The cubic root of 920991 is about 97.2937916676.

The spelling of 920991 in words is "nine hundred twenty thousand, nine hundred ninety-one".