81901500 has 48 divisors (see below), whose sum is σ = 238501536. Its totient is φ = 21840000.

The previous prime is 81901493. The next prime is 81901507. The reversal of 81901500 is 510918.

It is an interprime number because it is at equal distance from previous prime (81901493) and next prime (81901507).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81901507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25801 + ... + 28800.

It is an arithmetic number, because the mean of its divisors is an integer number (4968782).

Almost surely, 2^81901500 is an apocalyptic number.

It is an amenable number.

81901500 is an abundant number, since it is smaller than the sum of its proper divisors (156600036).

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

81901500 is a wasteful number, since it uses less digits than its factorization.

81901500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54623 (or 54611 counting only the distinct ones).

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

The square root of 81901500 is about 9049.9447512126. The cubic root of 81901500 is about 434.2741230129.

The spelling of 81901500 in words is "eighty-one million, nine hundred one thousand, five hundred".