81357312 has 40 divisors (see below), whose sum is σ = 216745056. Its totient is φ = 27118592.

The previous prime is 81357307. The next prime is 81357317. The reversal of 81357312 is 21375318.

It is an interprime number because it is at equal distance from previous prime (81357307) and next prime (81357317).

It is a self number, because there is not a number n which added to its sum of digits gives 81357312.

It is not an unprimeable number, because it can be changed into a prime (81357317) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24948 + ... + 28019.

Almost surely, 2^81357312 is an apocalyptic number.

It is an amenable number.

81357312 is an abundant number, since it is smaller than the sum of its proper divisors (135387744).

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

81357312 is an equidigital number, since it uses as much as digits as its factorization.

81357312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52988 (or 52972 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 81357312 is about 9019.8288232095. The cubic root of 81357312 is about 433.3101515541.

The spelling of 81357312 in words is "eighty-one million, three hundred fifty-seven thousand, three hundred twelve".