81838257 has 8 divisors (see below), whose sum is σ = 109169376. Its totient is φ = 54532992.

The previous prime is 81838247. The next prime is 81838277. The reversal of 81838257 is 75283818.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81838257 - 2⁴ = 81838241 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81838247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2838 + ... + 13104.

It is an arithmetic number, because the mean of its divisors is an integer number (13646172).

Almost surely, 2^81838257 is an apocalyptic number.

It is an amenable number.

81838257 is a deficient number, since it is larger than the sum of its proper divisors (27331119).

81838257 is a wasteful number, since it uses less digits than its factorization.

81838257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12927.

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

The square root of 81838257 is about 9046.4499666996. The cubic root of 81838257 is about 434.1623144352.

The spelling of 81838257 in words is "eighty-one million, eight hundred thirty-eight thousand, two hundred fifty-seven".