81749267899 has 8 divisors (see below), whose sum is σ = 88040432480. Its totient is φ = 75458497536.

The previous prime is 81749267879. The next prime is 81749267923. The reversal of 81749267899 is 99876294718.

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

It is a cyclic number.

It is not a de Polignac number, because 81749267899 - 2²³ = 81740879291 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81749267819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 441979 + ... + 599035.

It is an arithmetic number, because the mean of its divisors is an integer number (11005054060).

Almost surely, 2^81749267899 is an apocalyptic number.

81749267899 is a deficient number, since it is larger than the sum of its proper divisors (6291164581).

81749267899 is a wasteful number, since it uses less digits than its factorization.

81749267899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197109.

The product of its digits is 109734912, while the sum is 70.

The spelling of 81749267899 in words is "eighty-one billion, seven hundred forty-nine million, two hundred sixty-seven thousand, eight hundred ninety-nine".