81149038491 has 4 divisors (see below), whose sum is σ = 108198717992. Its totient is φ = 54099358992.

The previous prime is 81149038469. The next prime is 81149038499. The reversal of 81149038491 is 19483094118.

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

It is not a de Polignac number, because 81149038491 - 2⁵ = 81149038459 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81149038491.

It is not an unprimeable number, because it can be changed into a prime (81149038499) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13524839746 + ... + 13524839751.

It is an arithmetic number, because the mean of its divisors is an integer number (27049679498).

Almost surely, 2^81149038491 is an apocalyptic number.

81149038491 is a deficient number, since it is larger than the sum of its proper divisors (27049679501).

81149038491 is a wasteful number, since it uses less digits than its factorization.

81149038491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27049679500.

The product of its (nonzero) digits is 248832, while the sum is 48.

The spelling of 81149038491 in words is "eighty-one billion, one hundred forty-nine million, thirty-eight thousand, four hundred ninety-one".