81764899 has 2 divisors, whose sum is σ = 81764900. Its totient is φ = 81764898.

The previous prime is 81764869. The next prime is 81764909. The reversal of 81764899 is 99846718.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81764899 is a prime.

It is not a weakly prime, because it can be changed into another prime (81764869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40882449 + 40882450.

It is an arithmetic number, because the mean of its divisors is an integer number (40882450).

Almost surely, 2^81764899 is an apocalyptic number.

81764899 is a deficient number, since it is larger than the sum of its proper divisors (1).

81764899 is an equidigital number, since it uses as much as digits as its factorization.

81764899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 52.

The square root of 81764899 is about 9042.3945390588. The cubic root of 81764899 is about 434.0325511627.

The spelling of 81764899 in words is "eighty-one million, seven hundred sixty-four thousand, eight hundred ninety-nine".