81292238645 has 4 divisors (see below), whose sum is σ = 97550686380. Its totient is φ = 65033790912.

The previous prime is 81292238639. The next prime is 81292238669. The reversal of 81292238645 is 54683229218.

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

It can be written as a sum of positive squares in 2 ways, for example, as 54319760356 + 26972478289 = 233066^2 + 164233^2 .

It is a cyclic number.

It is not a de Polignac number, because 81292238645 - 2⁸ = 81292238389 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81292238593 and 81292238602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8129223860 + ... + 8129223869.

It is an arithmetic number, because the mean of its divisors is an integer number (24387671595).

Almost surely, 2^81292238645 is an apocalyptic number.

It is an amenable number.

81292238645 is a deficient number, since it is larger than the sum of its proper divisors (16258447735).

81292238645 is a wasteful number, since it uses less digits than its factorization.

81292238645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16258447734.

The product of its digits is 1658880, while the sum is 50.

The spelling of 81292238645 in words is "eighty-one billion, two hundred ninety-two million, two hundred thirty-eight thousand, six hundred forty-five".