81162100 has 36 divisors (see below), whose sum is σ = 177419200. Its totient is φ = 32225760.

The previous prime is 81162071. The next prime is 81162121. The reversal of 81162100 is 126118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10981 + ... + 16819.

Almost surely, 2^81162100 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81162100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88709600).

81162100 is an abundant number, since it is smaller than the sum of its proper divisors (96257100).

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

81162100 is a wasteful number, since it uses less digits than its factorization.

81162100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5992 (or 5985 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 81162100 is about 9009.0010545010. The cubic root of 81162100 is about 432.9633067381.

Subtracting from 81162100 its sum of digits (19), we obtain a square (81162081 = 9009²).

Adding to 81162100 its reverse (126118), we get a palindrome (81288218).

The spelling of 81162100 in words is "eighty-one million, one hundred sixty-two thousand, one hundred".