81231744 has 64 divisors (see below), whose sum is σ = 235399680. Its totient is φ = 24614400.

The previous prime is 81231743. The next prime is 81231751. The reversal of 81231744 is 44713218.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81231743) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5392 + ... + 13839.

It is an arithmetic number, because the mean of its divisors is an integer number (3678120).

Almost surely, 2^81231744 is an apocalyptic number.

It is an amenable number.

81231744 is an abundant number, since it is smaller than the sum of its proper divisors (154167936).

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

81231744 is a wasteful number, since it uses less digits than its factorization.

81231744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19259 (or 19247 counting only the distinct ones).

The product of its digits is 5376, while the sum is 30.

The square root of 81231744 is about 9012.8654710919. The cubic root of 81231744 is about 433.0871111409.

The spelling of 81231744 in words is "eighty-one million, two hundred thirty-one thousand, seven hundred forty-four".