909981 has 8 divisors (see below), whose sum is σ = 1348160. Its totient is φ = 606636.

The previous prime is 909977. The next prime is 910003. The reversal of 909981 is 189909.

It is not a de Polignac number, because 909981 - 2² = 909977 is a prime.

It is a super-2 number, since 2×909981² = 1656130840722, which contains 22 as substring.

It is a Duffinian number.

909981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (909901) 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, 16825 + ... + 16878.

It is an arithmetic number, because the mean of its divisors is an integer number (168520).

2⁹⁰⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

909981 is a deficient number, since it is larger than the sum of its proper divisors (438179).

909981 is a wasteful number, since it uses less digits than its factorization.

909981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33712 (or 33706 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 909981 is about 953.9292426590. The cubic root of 909981 is about 96.9045363978.

It can be divided in two parts, 9099 and 81, that added together give a triangular number (9180 = T₁₃₅).

The spelling of 909981 in words is "nine hundred nine thousand, nine hundred eighty-one".