81495561633 has 4 divisors (see below), whose sum is σ = 108660748848. Its totient is φ = 54330374420.

The previous prime is 81495561611. The next prime is 81495561659. The reversal of 81495561633 is 33616559418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81495561633 - 2⁸ = 81495561377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81495560633) 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, 13582593603 + ... + 13582593608.

It is an arithmetic number, because the mean of its divisors is an integer number (27165187212).

Almost surely, 2^81495561633 is an apocalyptic number.

It is an amenable number.

81495561633 is a deficient number, since it is larger than the sum of its proper divisors (27165187215).

81495561633 is a wasteful number, since it uses less digits than its factorization.

81495561633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27165187214.

The product of its digits is 2332800, while the sum is 51.

The spelling of 81495561633 in words is "eighty-one billion, four hundred ninety-five million, five hundred sixty-one thousand, six hundred thirty-three".