81913650 has 192 divisors, whose sum is σ = 265483008. Its totient is φ = 16220160.

The previous prime is 81913627. The next prime is 81913669. The reversal of 81913650 is 5631918.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 231874 + ... + 232226.

It is an arithmetic number, because the mean of its divisors is an integer number (1382724).

Almost surely, 2^81913650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81913650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132741504).

81913650 is an abundant number, since it is smaller than the sum of its proper divisors (183569358).

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

81913650 is a wasteful number, since it uses less digits than its factorization.

81913650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405 (or 400 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 81913650 is about 9050.6160011350. The cubic root of 81913650 is about 434.2955966518.

The spelling of 81913650 in words is "eighty-one million, nine hundred thirteen thousand, six hundred fifty".