81951744 has 176 divisors, whose sum is σ = 258871808. Its totient is φ = 22560768.

The previous prime is 81951733. The next prime is 81951757. The reversal of 81951744 is 44715918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 795597 + ... + 795699.

Almost surely, 2^81951744 is an apocalyptic number.

81951744 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 81951744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129435904).

81951744 is an abundant number, since it is smaller than the sum of its proper divisors (176920064).

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

81951744 is a wasteful number, since it uses less digits than its factorization.

81951744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 152 counting only the distinct ones).

The product of its digits is 40320, while the sum is 39.

The square root of 81951744 is about 9052.7202541557. The cubic root of 81951744 is about 434.3629093748.

The spelling of 81951744 in words is "eighty-one million, nine hundred fifty-one thousand, seven hundred forty-four".