81646590147 has 4 divisors (see below), whose sum is σ = 108862120200. Its totient is φ = 54431060096.

The previous prime is 81646590133. The next prime is 81646590167. The reversal of 81646590147 is 74109564618.

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

It is a cyclic number.

It is not a de Polignac number, because 81646590147 - 2¹¹ = 81646588099 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81646590147.

It is not an unprimeable number, because it can be changed into a prime (81646590167) 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, 13607765022 + ... + 13607765027.

It is an arithmetic number, because the mean of its divisors is an integer number (27215530050).

Almost surely, 2^81646590147 is an apocalyptic number.

81646590147 is a deficient number, since it is larger than the sum of its proper divisors (27215530053).

81646590147 is a wasteful number, since it uses less digits than its factorization.

81646590147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27215530052.

The product of its (nonzero) digits is 1451520, while the sum is 51.

The spelling of 81646590147 in words is "eighty-one billion, six hundred forty-six million, five hundred ninety thousand, one hundred forty-seven".