81900143 has 4 divisors (see below), whose sum is σ = 88200168. Its totient is φ = 75600120.

The previous prime is 81900139. The next prime is 81900163. The reversal of 81900143 is 34100918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34100918 = 2 ⋅17050459.

It is a cyclic number.

It is not a de Polignac number, because 81900143 - 2² = 81900139 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81900113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3149993 + ... + 3150018.

It is an arithmetic number, because the mean of its divisors is an integer number (22050042).

Almost surely, 2^81900143 is an apocalyptic number.

81900143 is a deficient number, since it is larger than the sum of its proper divisors (6300025).

81900143 is a wasteful number, since it uses less digits than its factorization.

81900143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6300024.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 81900143 is about 9049.8697780686. The cubic root of 81900143 is about 434.2717245496.

The spelling of 81900143 in words is "eighty-one million, nine hundred thousand, one hundred forty-three".