81318648 has 32 divisors (see below), whose sum is σ = 207624960. Its totient is φ = 26529120.

The previous prime is 81318617. The next prime is 81318659. The reversal of 81318648 is 84681318.

It is a super-2 number, since 2×81318648² = 13225445025095808, which contains 22 as substring.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34918 + ... + 37173.

It is an arithmetic number, because the mean of its divisors is an integer number (6488280).

Almost surely, 2^81318648 is an apocalyptic number.

It is an amenable number.

81318648 is an abundant number, since it is smaller than the sum of its proper divisors (126306312).

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

81318648 is a wasteful number, since it uses less digits than its factorization.

81318648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72147 (or 72143 counting only the distinct ones).

The product of its digits is 36864, while the sum is 39.

The square root of 81318648 is about 9017.6852905832. The cubic root of 81318648 is about 433.2414990140.

The spelling of 81318648 in words is "eighty-one million, three hundred eighteen thousand, six hundred forty-eight".