81859251 has 16 divisors (see below), whose sum is σ = 112944128. Its totient is φ = 52682400.

The previous prime is 81859181. The next prime is 81859291. The reversal of 81859251 is 15295818.

It is not a de Polignac number, because 81859251 - 2⁷ = 81859123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81859291) 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, 49500 + ... + 51126.

It is an arithmetic number, because the mean of its divisors is an integer number (7059008).

Almost surely, 2^81859251 is an apocalyptic number.

81859251 is a deficient number, since it is larger than the sum of its proper divisors (31084877).

81859251 is a wasteful number, since it uses less digits than its factorization.

81859251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2202.

The product of its digits is 28800, while the sum is 39.

The square root of 81859251 is about 9047.6102369631. The cubic root of 81859251 is about 434.1994365370.

The spelling of 81859251 in words is "eighty-one million, eight hundred fifty-nine thousand, two hundred fifty-one".