81019500 has 48 divisors (see below), whose sum is σ = 235933152. Its totient is φ = 21604800.

The previous prime is 81019489. The next prime is 81019511. The reversal of 81019500 is 591018.

It is an interprime number because it is at equal distance from previous prime (81019489) and next prime (81019511).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25507 + ... + 28506.

It is an arithmetic number, because the mean of its divisors is an integer number (4915274).

Almost surely, 2^81019500 is an apocalyptic number.

It is an amenable number.

81019500 is an abundant number, since it is smaller than the sum of its proper divisors (154913652).

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

81019500 is a wasteful number, since it uses less digits than its factorization.

81019500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54035 (or 54023 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 24.

The square root of 81019500 is about 9001.0832681406. The cubic root of 81019500 is about 432.7095891293.

The spelling of 81019500 in words is "eighty-one million, nineteen thousand, five hundred".