81071698 has 4 divisors (see below), whose sum is σ = 121607550. Its totient is φ = 40535848.

The previous prime is 81071687. The next prime is 81071701. The reversal of 81071698 is 89617018.

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

It can be written as a sum of positive squares in only one way, i.e., 81054009 + 17689 = 9003^2 + 133^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 81071698.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20267923 + ... + 20267926.

Almost surely, 2^81071698 is an apocalyptic number.

81071698 is a deficient number, since it is larger than the sum of its proper divisors (40535852).

81071698 is a wasteful number, since it uses less digits than its factorization.

81071698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40535851.

The product of its (nonzero) digits is 24192, while the sum is 40.

The square root of 81071698 is about 9003.9823411644. The cubic root of 81071698 is about 432.8024956777.

The spelling of 81071698 in words is "eighty-one million, seventy-one thousand, six hundred ninety-eight".