81535900 has 36 divisors (see below), whose sum is σ = 179189920. Its totient is φ = 32198400.

The previous prime is 81535879. The next prime is 81535931. The reversal of 81535900 is 953518.

It is a congruent number.

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 in 11 ways as a sum of consecutive naturals, for example, 2740 + ... + 13060.

Almost surely, 2^81535900 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 81535900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89594960).

81535900 is an abundant number, since it is smaller than the sum of its proper divisors (97654020).

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

81535900 is a wasteful number, since it uses less digits than its factorization.

81535900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10414 (or 10407 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 81535900 is about 9029.7231408277. The cubic root of 81535900 is about 433.6269738874.

The spelling of 81535900 in words is "eighty-one million, five hundred thirty-five thousand, nine hundred".