81719232698 has 4 divisors (see below), whose sum is σ = 122578849050. Its totient is φ = 40859616348.

The previous prime is 81719232677. The next prime is 81719232709. The reversal of 81719232698 is 89623291718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89623291718 = 2 ⋅44811645859.

It can be written as a sum of positive squares in only one way, i.e., 79832807209 + 1886425489 = 282547^2 + 43433^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20429808173 + ... + 20429808176.

Almost surely, 2^81719232698 is an apocalyptic number.

81719232698 is a deficient number, since it is larger than the sum of its proper divisors (40859616352).

81719232698 is a wasteful number, since it uses less digits than its factorization.

81719232698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40859616351.

The product of its digits is 2612736, while the sum is 56.

The spelling of 81719232698 in words is "eighty-one billion, seven hundred nineteen million, two hundred thirty-two thousand, six hundred ninety-eight".