81006900 has 72 divisors (see below), whose sum is σ = 252421344. Its totient is φ = 19939200.

The previous prime is 81006839. The next prime is 81006907. The reversal of 81006900 is 960018.

It is a super-2 number, since 2×81006900² = 13124235695220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81006907) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6486 + ... + 14285.

It is an arithmetic number, because the mean of its divisors is an integer number (3505852).

Almost surely, 2^81006900 is an apocalyptic number.

It is an amenable number.

81006900 is an abundant number, since it is smaller than the sum of its proper divisors (171414444).

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

81006900 is a wasteful number, since it uses less digits than its factorization.

81006900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20801 (or 20794 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 81006900 is about 9000.3833251701. The cubic root of 81006900 is about 432.6871565731.

Adding to 81006900 its reverse (960018), we get a palindrome (81966918).

The spelling of 81006900 in words is "eighty-one million, six thousand, nine hundred".