81928330969 has 4 divisors (see below), whose sum is σ = 84753445860. Its totient is φ = 79103216080.

The previous prime is 81928330963. The next prime is 81928331033. The reversal of 81928330969 is 96903382918.

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 55347267600 + 26581063369 = 235260^2 + 163037^2 .

It is a cyclic number.

It is not a de Polignac number, because 81928330969 - 2⁵ = 81928330937 is a prime.

It is a super-2 number, since 2×81928330969² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81928330963) 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, 1412557402 + ... + 1412557459.

It is an arithmetic number, because the mean of its divisors is an integer number (21188361465).

Almost surely, 2^81928330969 is an apocalyptic number.

It is an amenable number.

81928330969 is a deficient number, since it is larger than the sum of its proper divisors (2825114891).

81928330969 is a wasteful number, since it uses less digits than its factorization.

81928330969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2825114890.

The product of its (nonzero) digits is 5038848, while the sum is 58.

The spelling of 81928330969 in words is "eighty-one billion, nine hundred twenty-eight million, three hundred thirty thousand, nine hundred sixty-nine".