81512699 has 2 divisors, whose sum is σ = 81512700. Its totient is φ = 81512698.

The previous prime is 81512681. The next prime is 81512719. The reversal of 81512699 is 99621518.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81512699 - 2²⁴ = 64735483 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_4752698 and since 81512699 and 4752698 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81512999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40756349 + 40756350.

It is an arithmetic number, because the mean of its divisors is an integer number (40756350).

Almost surely, 2^81512699 is an apocalyptic number.

81512699 is a deficient number, since it is larger than the sum of its proper divisors (1).

81512699 is an equidigital number, since it uses as much as digits as its factorization.

81512699 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 41.

The square root of 81512699 is about 9028.4383477986. The cubic root of 81512699 is about 433.5858405387.

The spelling of 81512699 in words is "eighty-one million, five hundred twelve thousand, six hundred ninety-nine".