81780384764 has 12 divisors (see below), whose sum is σ = 154124571384. Its totient is φ = 37744792944.

The previous prime is 81780384761. The next prime is 81780384767. The reversal of 81780384764 is 46748308718.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81780384761) and next prime (81780384767).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81780384761) 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, 786349802 + ... + 786349905.

It is an arithmetic number, because the mean of its divisors is an integer number (12843714282).

Almost surely, 2^81780384764 is an apocalyptic number.

It is an amenable number.

81780384764 is a deficient number, since it is larger than the sum of its proper divisors (72344186620).

81780384764 is a wasteful number, since it uses less digits than its factorization.

81780384764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1572699724 (or 1572699722 counting only the distinct ones).

The product of its (nonzero) digits is 7225344, while the sum is 56.

The spelling of 81780384764 in words is "eighty-one billion, seven hundred eighty million, three hundred eighty-four thousand, seven hundred sixty-four".