809306981 has 24 divisors (see below), whose sum is σ = 1010548440. Its totient is φ = 643894272.

The previous prime is 809306977. The next prime is 809307007. The reversal of 809306981 is 189603908.

It can be written as a sum of positive squares in 4 ways, for example, as 40132225 + 769174756 = 6335^2 + 27734^2 .

It is not a de Polignac number, because 809306981 - 2² = 809306977 is a prime.

It is a super-2 number, since 2×809306981² = 1309955578990668722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809306921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54155 + ... + 67463.

It is an arithmetic number, because the mean of its divisors is an integer number (42106185).

Almost surely, 2^809306981 is an apocalyptic number.

It is an amenable number.

809306981 is a deficient number, since it is larger than the sum of its proper divisors (201241459).

809306981 is a wasteful number, since it uses less digits than its factorization.

809306981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13413 (or 13406 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 809306981 is about 28448.3212334225. The cubic root of 809306981 is about 931.9038276402.

The spelling of 809306981 in words is "eight hundred nine million, three hundred six thousand, nine hundred eighty-one".