81399698 has 8 divisors (see below), whose sum is σ = 122312892. Its totient is φ = 40628736.

The previous prime is 81399673. The next prime is 81399701. The reversal of 81399698 is 89699318.

It can be written as a sum of positive squares in 2 ways, for example, as 52809289 + 28590409 = 7267^2 + 5347^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34115 + ... + 36422.

Almost surely, 2^81399698 is an apocalyptic number.

81399698 is a deficient number, since it is larger than the sum of its proper divisors (40913194).

81399698 is a wasteful number, since it uses less digits than its factorization.

81399698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71116.

The product of its digits is 839808, while the sum is 53.

The square root of 81399698 is about 9022.1781183925. The cubic root of 81399698 is about 433.3853879610.

The spelling of 81399698 in words is "eighty-one million, three hundred ninety-nine thousand, six hundred ninety-eight".