91681936394 has 16 divisors (see below), whose sum is σ = 147113652168. Its totient is φ = 42699651072.

The previous prime is 91681936373. The next prime is 91681936441. The reversal of 91681936394 is 49363918619.

It can be written as a sum of positive squares in 4 ways, for example, as 79080751369 + 12601185025 = 281213^2 + 112255^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13896329 + ... + 13902924.

Almost surely, 2^91681936394 is an apocalyptic number.

91681936394 is a deficient number, since it is larger than the sum of its proper divisors (55431715774).

91681936394 is a wasteful number, since it uses less digits than its factorization.

91681936394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27799369.

The product of its digits is 7558272, while the sum is 59.

The spelling of 91681936394 in words is "ninety-one billion, six hundred eighty-one million, nine hundred thirty-six thousand, three hundred ninety-four".