81572198398 has 4 divisors (see below), whose sum is σ = 122358297600. Its totient is φ = 40786099198.

The previous prime is 81572198377. The next prime is 81572198503. The reversal of 81572198398 is 89389127518.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20393049598 + ... + 20393049601.

It is an arithmetic number, because the mean of its divisors is an integer number (30589574400).

Almost surely, 2^81572198398 is an apocalyptic number.

81572198398 is a deficient number, since it is larger than the sum of its proper divisors (40786099202).

81572198398 is a wasteful number, since it uses less digits than its factorization.

81572198398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40786099201.

The product of its digits is 8709120, while the sum is 61.

The spelling of 81572198398 in words is "eighty-one billion, five hundred seventy-two million, one hundred ninety-eight thousand, three hundred ninety-eight".