81917132 has 24 divisors (see below), whose sum is σ = 164619840. Its totient is φ = 35274960.

The previous prime is 81917123. The next prime is 81917137. The reversal of 81917132 is 23171918.

It is not an unprimeable number, because it can be changed into a prime (81917137) 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, 48158 + ... + 49829.

It is an arithmetic number, because the mean of its divisors is an integer number (6859160).

Almost surely, 2^81917132 is an apocalyptic number.

It is an amenable number.

81917132 is an abundant number, since it is smaller than the sum of its proper divisors (82702708).

81917132 is a wasteful number, since it uses less digits than its factorization.

81917132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98021 (or 98019 counting only the distinct ones).

The product of its digits is 3024, while the sum is 32.

The square root of 81917132 is about 9050.8083616879. The cubic root of 81917132 is about 434.3017502694.

The spelling of 81917132 in words is "eighty-one million, nine hundred seventeen thousand, one hundred thirty-two".