81913648 has 10 divisors (see below), whose sum is σ = 158707724. Its totient is φ = 40956816.

The previous prime is 81913627. The next prime is 81913669. The reversal of 81913648 is 84631918.

It is an interprime number because it is at equal distance from previous prime (81913627) and next prime (81913669).

It is a self number, because there is not a number n which added to its sum of digits gives 81913648.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2559786 + ... + 2559817.

Almost surely, 2^81913648 is an apocalyptic number.

It is an amenable number.

81913648 is a deficient number, since it is larger than the sum of its proper divisors (76794076).

81913648 is a wasteful number, since it uses less digits than its factorization.

81913648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5119611 (or 5119605 counting only the distinct ones).

The product of its digits is 41472, while the sum is 40.

The square root of 81913648 is about 9050.6158906452. The cubic root of 81913648 is about 434.2955931172.

The spelling of 81913648 in words is "eighty-one million, nine hundred thirteen thousand, six hundred forty-eight".