81397488 has 20 divisors (see below), whose sum is σ = 210276968. Its totient is φ = 27132480.

The previous prime is 81397487. The next prime is 81397499. The reversal of 81397488 is 88479318.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48), and also a Moran number because the ratio is a prime number: 1695781 = 81397488 / (8 + 1 + 3 + 9 + 7 + 4 + 8 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81397487) 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, 847843 + ... + 847938.

Almost surely, 2^81397488 is an apocalyptic number.

It is an amenable number.

81397488 is an abundant number, since it is smaller than the sum of its proper divisors (128879480).

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

81397488 is a wasteful number, since it uses less digits than its factorization.

81397488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1695792 (or 1695786 counting only the distinct ones).

The product of its digits is 387072, while the sum is 48.

The square root of 81397488 is about 9022.0556415930. The cubic root of 81397488 is about 433.3814657909.

The spelling of 81397488 in words is "eighty-one million, three hundred ninety-seven thousand, four hundred eighty-eight".