81858237 has 16 divisors (see below), whose sum is σ = 110858880. Its totient is φ = 53721792.

The previous prime is 81858221. The next prime is 81858241. The reversal of 81858237 is 73285818.

It is a happy number.

It is not a de Polignac number, because 81858237 - 2⁴ = 81858221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81858037) 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, 55848 + ... + 57294.

It is an arithmetic number, because the mean of its divisors is an integer number (6928680).

Almost surely, 2^81858237 is an apocalyptic number.

It is an amenable number.

81858237 is a deficient number, since it is larger than the sum of its proper divisors (29000643).

81858237 is a wasteful number, since it uses less digits than its factorization.

81858237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1732.

The product of its digits is 107520, while the sum is 42.

The square root of 81858237 is about 9047.5541998929. The cubic root of 81858237 is about 434.1976437034.

The spelling of 81858237 in words is "eighty-one million, eight hundred fifty-eight thousand, two hundred thirty-seven".