81864264738851 has 4 divisors (see below), whose sum is σ = 93559159701552. Its totient is φ = 70169369776152.

The previous prime is 81864264738709. The next prime is 81864264738877. The reversal of 81864264738851 is 15883746246818.

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 81864264738851 - 2²⁶ = 81864197629987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81864264738881) 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, 5847447481340 + ... + 5847447481353.

It is an arithmetic number, because the mean of its divisors is an integer number (23389789925388).

Almost surely, 2^{81864264738851} is an apocalyptic number.

81864264738851 is a deficient number, since it is larger than the sum of its proper divisors (11694894962701).

81864264738851 is a wasteful number, since it uses less digits than its factorization.

81864264738851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11694894962700.

The product of its digits is 495452160, while the sum is 71.

The spelling of 81864264738851 in words is "eighty-one trillion, eight hundred sixty-four billion, two hundred sixty-four million, seven hundred thirty-eight thousand, eight hundred fifty-one".