81185748 has 36 divisors (see below), whose sum is σ = 220362912. Its totient is φ = 23195760.

The previous prime is 81185747. The next prime is 81185773. The reversal of 81185748 is 84758118.

It is a super-2 number, since 2×81185748² = 13182251356639008, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81185743) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68448 + ... + 69623.

It is an arithmetic number, because the mean of its divisors is an integer number (6121192).

Almost surely, 2^81185748 is an apocalyptic number.

It is an amenable number.

81185748 is an abundant number, since it is smaller than the sum of its proper divisors (139177164).

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

81185748 is a wasteful number, since it uses less digits than its factorization.

81185748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138092 (or 138083 counting only the distinct ones).

The product of its digits is 71680, while the sum is 42.

The square root of 81185748 is about 9010.3134240713. The cubic root of 81185748 is about 433.0053531368.

The spelling of 81185748 in words is "eighty-one million, one hundred eighty-five thousand, seven hundred forty-eight".