81816763392 has 704 divisors, whose sum is σ = 308130816000. Its totient is φ = 20862074880.

The previous prime is 81816763381. The next prime is 81816763403. The reversal of 81816763392 is 29336761818.

81816763392 is a `hidden beast` number, since 8 + 181 + 6 + 76 + 3 + 392 = 666.

It is an interprime number because it is at equal distance from previous prime (81816763381) and next prime (81816763403).

It is a super-2 number, since 2×81816763392² (a number of 23 digits) contains 22 as substring.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 77994484 + ... + 77995532.

Almost surely, 2^81816763392 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81816763392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154065408000).

81816763392 is an abundant number, since it is smaller than the sum of its proper divisors (226314052608).

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

81816763392 is a wasteful number, since it uses less digits than its factorization.

81816763392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1129 (or 1105 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 81816763392 in words is "eighty-one billion, eight hundred sixteen million, seven hundred sixty-three thousand, three hundred ninety-two".