81861733 has 16 divisors (see below), whose sum is σ = 86780160. Its totient is φ = 77137216.

The previous prime is 81861727. The next prime is 81861737. The reversal of 81861733 is 33716818.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81861733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81861692 and 81861701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81861737) 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, 146691 + ... + 147247.

It is an arithmetic number, because the mean of its divisors is an integer number (5423760).

Almost surely, 2^81861733 is an apocalyptic number.

It is an amenable number.

81861733 is a deficient number, since it is larger than the sum of its proper divisors (4918427).

81861733 is a wasteful number, since it uses less digits than its factorization.

81861733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716.

The product of its digits is 24192, while the sum is 37.

The square root of 81861733 is about 9047.7473992149. The cubic root of 81861733 is about 434.2038248503.

The spelling of 81861733 in words is "eighty-one million, eight hundred sixty-one thousand, seven hundred thirty-three".