81899741 has 16 divisors (see below), whose sum is σ = 105632640. Its totient is φ = 61615680.

The previous prime is 81899717. The next prime is 81899767. The reversal of 81899741 is 14799818.

It is not a de Polignac number, because 81899741 - 2²⁶ = 14790877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81899771) 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, 16106 + ... + 20571.

It is an arithmetic number, because the mean of its divisors is an integer number (6602040).

Almost surely, 2^81899741 is an apocalyptic number.

It is an amenable number.

81899741 is a deficient number, since it is larger than the sum of its proper divisors (23732899).

81899741 is a wasteful number, since it uses less digits than its factorization.

81899741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36724.

The product of its digits is 145152, while the sum is 47.

The square root of 81899741 is about 9049.8475677770. The cubic root of 81899741 is about 434.2710140196.

The spelling of 81899741 in words is "eighty-one million, eight hundred ninety-nine thousand, seven hundred forty-one".