81891846 has 12 divisors (see below), whose sum is σ = 177432372. Its totient is φ = 27297276.

The previous prime is 81891833. The next prime is 81891847. The reversal of 81891846 is 64819818.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81891847) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2274756 + ... + 2274791.

It is an arithmetic number, because the mean of its divisors is an integer number (14786031).

Almost surely, 2^81891846 is an apocalyptic number.

81891846 is an abundant number, since it is smaller than the sum of its proper divisors (95540526).

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

81891846 is a wasteful number, since it uses less digits than its factorization.

81891846 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4549555 (or 4549552 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 81891846 is about 9049.4113620721. The cubic root of 81891846 is about 434.2570592346.

The spelling of 81891846 in words is "eighty-one million, eight hundred ninety-one thousand, eight hundred forty-six".