81572767984 has 10 divisors (see below), whose sum is σ = 158047238000. Its totient is φ = 40786383984.

The previous prime is 81572767973. The next prime is 81572768009. The reversal of 81572767984 is 48976727518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2549148984 + ... + 2549149015.

It is an arithmetic number, because the mean of its divisors is an integer number (15804723800).

Almost surely, 2^81572767984 is an apocalyptic number.

It is an amenable number.

81572767984 is a deficient number, since it is larger than the sum of its proper divisors (76474470016).

81572767984 is a wasteful number, since it uses less digits than its factorization.

81572767984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5098298007 (or 5098298001 counting only the distinct ones).

The product of its digits is 47416320, while the sum is 64.

It can be divided in two parts, 81572 and 767984, that added together give a triangular number (849556 = T₁₃₀₃).

The spelling of 81572767984 in words is "eighty-one billion, five hundred seventy-two million, seven hundred sixty-seven thousand, nine hundred eighty-four".