905921 has 4 divisors (see below), whose sum is σ = 914052. Its totient is φ = 897792.

The previous prime is 905917. The next prime is 905923. The reversal of 905921 is 129509.

It is a happy number.

905921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 207025 + 698896 = 455^2 + 836^2 .

It is a cyclic number.

It is not a de Polignac number, because 905921 - 2² = 905917 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 905921.

It is not an unprimeable number, because it can be changed into a prime (905923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3896 + ... + 4121.

It is an arithmetic number, because the mean of its divisors is an integer number (228513).

2⁹⁰⁵⁹²¹ is an apocalyptic number.

It is an amenable number.

905921 is a deficient number, since it is larger than the sum of its proper divisors (8131).

905921 is a wasteful number, since it uses less digits than its factorization.

905921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8130.

The product of its (nonzero) digits is 810, while the sum is 26.

The square root of 905921 is about 951.7988232815. The cubic root of 905921 is about 96.7602040841.

The spelling of 905921 in words is "nine hundred five thousand, nine hundred twenty-one".