81156155647 has 16 divisors (see below), whose sum is σ = 97673264640. Its totient is φ = 65873024928.

The previous prime is 81156155621. The next prime is 81156155693. The reversal of 81156155647 is 74655165118.

It is not a de Polignac number, because 81156155647 - 2³¹ = 79008671999 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81156155647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81156155147) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184038 + ... + 442924.

It is an arithmetic number, because the mean of its divisors is an integer number (6104579040).

Almost surely, 2^81156155647 is an apocalyptic number.

81156155647 is a deficient number, since it is larger than the sum of its proper divisors (16517108993).

81156155647 is a wasteful number, since it uses less digits than its factorization.

81156155647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261270.

The product of its digits is 1008000, while the sum is 49.

The spelling of 81156155647 in words is "eighty-one billion, one hundred fifty-six million, one hundred fifty-five thousand, six hundred forty-seven".