81663498 has 64 divisors (see below), whose sum is σ = 211680000. Its totient is φ = 23327136.

The previous prime is 81663497. The next prime is 81663503. The reversal of 81663498 is 89436618.

81663498 is a `hidden beast` number, since 8 + 1 + 6 + 634 + 9 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (81663497) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16318 + ... + 20726.

It is an arithmetic number, because the mean of its divisors is an integer number (3307500).

Almost surely, 2^81663498 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81663498, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105840000).

81663498 is an abundant number, since it is smaller than the sum of its proper divisors (130016502).

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

81663498 is a wasteful number, since it uses less digits than its factorization.

81663498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4441 (or 4421 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 81663498 is about 9036.7858224039. The cubic root of 81663498 is about 433.8530546574.

It can be divided in two parts, 8166 and 3498, that added together give a square (11664 = 108²).

The spelling of 81663498 in words is "eighty-one million, six hundred sixty-three thousand, four hundred ninety-eight".