81774332784 has 70 divisors (see below), whose sum is σ = 237548020656. Its totient is φ = 27258107040.

The previous prime is 81774332753. The next prime is 81774332789. The reversal of 81774332784 is 48723347718.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 81774332784.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81774332789) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 3493752 + ... + 3517079.

Almost surely, 2^81774332784 is an apocalyptic number.

It is an amenable number.

81774332784 is an abundant number, since it is smaller than the sum of its proper divisors (155773687872).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81774332784 is an equidigital number, since it uses as much as digits as its factorization.

81774332784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7010857 (or 7010836 counting only the distinct ones).

The product of its digits is 6322176, while the sum is 54.

The spelling of 81774332784 in words is "eighty-one billion, seven hundred seventy-four million, three hundred thirty-two thousand, seven hundred eighty-four".