81974699 has 2 divisors, whose sum is σ = 81974700. Its totient is φ = 81974698.

The previous prime is 81974689. The next prime is 81974723. The reversal of 81974699 is 99647918.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81974699 - 2²⁰ = 80926123 is a prime.

It is a super-2 number, since 2×81974699² = 13439702552281202, which contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81974699.

It is not a weakly prime, because it can be changed into another prime (81974689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40987349 + 40987350.

It is an arithmetic number, because the mean of its divisors is an integer number (40987350).

Almost surely, 2^81974699 is an apocalyptic number.

81974699 is a deficient number, since it is larger than the sum of its proper divisors (1).

81974699 is an equidigital number, since it uses as much as digits as its factorization.

81974699 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 53.

The square root of 81974699 is about 9053.9880163384. The cubic root of 81974699 is about 434.4034611650.

The spelling of 81974699 in words is "eighty-one million, nine hundred seventy-four thousand, six hundred ninety-nine".