81764542971 has 24 divisors (see below), whose sum is σ = 124000465680. Its totient is φ = 51844516416.

The previous prime is 81764542963. The next prime is 81764542991. The reversal of 81764542971 is 17924546718.

81764542971 is a `hidden beast` number, since 8 + 1 + 7 + 6 + 4 + 542 + 97 + 1 = 666.

It is not a de Polignac number, because 81764542971 - 2³ = 81764542963 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81764542991) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2320380 + ... + 2355353.

It is an arithmetic number, because the mean of its divisors is an integer number (5166686070).

Almost surely, 2^81764542971 is an apocalyptic number.

81764542971 is a deficient number, since it is larger than the sum of its proper divisors (42235922709).

81764542971 is a wasteful number, since it uses less digits than its factorization.

81764542971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4675835 (or 4675832 counting only the distinct ones).

The product of its digits is 3386880, while the sum is 54.

Adding to 81764542971 its sum of digits (54), we get a square (81764543025 = 285945²).

The spelling of 81764542971 in words is "eighty-one billion, seven hundred sixty-four million, five hundred forty-two thousand, nine hundred seventy-one".