812923981 has 2 divisors, whose sum is σ = 812923982. Its totient is φ = 812923980.

The previous prime is 812923967. The next prime is 812924023. The reversal of 812923981 is 189329218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 569251881 + 243672100 = 23859^2 + 15610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-812923981 is a prime.

It is a super-2 number, since 2×812923981² = 1321690797769776722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (812923081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406461990 + 406461991.

It is an arithmetic number, because the mean of its divisors is an integer number (406461991).

Almost surely, 2^812923981 is an apocalyptic number.

It is an amenable number.

812923981 is a deficient number, since it is larger than the sum of its proper divisors (1).

812923981 is an equidigital number, since it uses as much as digits as its factorization.

812923981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 43.

The square root of 812923981 is about 28511.8217762387. The cubic root of 812923981 is about 933.2900700893.

The spelling of 812923981 in words is "eight hundred twelve million, nine hundred twenty-three thousand, nine hundred eighty-one".