81922857744 has 720 divisors, whose sum is σ = 287742916608. Its totient is φ = 19898597376.

The previous prime is 81922857743. The next prime is 81922857851. The reversal of 81922857744 is 44775822918.

It is a super-2 number, since 2×81922857744² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81922857743) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 645061809 + ... + 645061935.

Almost surely, 2^81922857744 is an apocalyptic number.

81922857744 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81922857744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143871458304).

81922857744 is an abundant number, since it is smaller than the sum of its proper divisors (205820058864).

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

81922857744 is a wasteful number, since it uses less digits than its factorization.

81922857744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272 (or 242 counting only the distinct ones).

The product of its digits is 9031680, while the sum is 57.

The spelling of 81922857744 in words is "eighty-one billion, nine hundred twenty-two million, eight hundred fifty-seven thousand, seven hundred forty-four".