81331152 has 40 divisors (see below), whose sum is σ = 240121536. Its totient is φ = 23237376.

The previous prime is 81331147. The next prime is 81331157. The reversal of 81331152 is 25113318.

It is an interprime number because it is at equal distance from previous prime (81331147) and next prime (81331157).

It is a super-2 number, since 2×81331152² = 13229512571294208, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81331157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120693 + ... + 121364.

Almost surely, 2^81331152 is an apocalyptic number.

It is an amenable number.

81331152 is an abundant number, since it is smaller than the sum of its proper divisors (158790384).

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

81331152 is a wasteful number, since it uses less digits than its factorization.

81331152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242075 (or 242069 counting only the distinct ones).

The product of its digits is 720, while the sum is 24.

The square root of 81331152 is about 9018.3785682350. The cubic root of 81331152 is about 433.2637037367.

The spelling of 81331152 in words is "eighty-one million, three hundred thirty-one thousand, one hundred fifty-two".