905981 has 8 divisors (see below), whose sum is σ = 968760. Its totient is φ = 844288.

The previous prime is 905963. The next prime is 905999. The reversal of 905981 is 189509.

It is an interprime number because it is at equal distance from previous prime (905963) and next prime (905999).

It can be written as a sum of positive squares in 4 ways, for example, as 168100 + 737881 = 410^2 + 859^2 .

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

It is not a de Polignac number, because 905981 - 2⁶ = 905917 is a prime.

It is a super-2 number, since 2×905981² = 1641603144722, which contains 22 as substring.

It is a Duffinian 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 905981.

It is not an unprimeable number, because it can be changed into a prime (905951) 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, 2135 + ... + 2523.

It is an arithmetic number, because the mean of its divisors is an integer number (121095).

2⁹⁰⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

905981 is a deficient number, since it is larger than the sum of its proper divisors (62779).

905981 is a wasteful number, since it uses less digits than its factorization.

905981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543.

The product of its (nonzero) digits is 3240, while the sum is 32.

The square root of 905981 is about 951.8303420253. The cubic root of 905981 is about 96.7623402101.

The spelling of 905981 in words is "nine hundred five thousand, nine hundred eighty-one".