81855129 has 8 divisors (see below), whose sum is σ = 109658272. Its totient is φ = 54311040.

The previous prime is 81855127. The next prime is 81855131. The reversal of 81855129 is 92155818.

It is an interprime number because it is at equal distance from previous prime (81855127) and next prime (81855131).

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

It is not a de Polignac number, because 81855129 - 2¹ = 81855127 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81855121) 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, 64024 + ... + 65289.

It is an arithmetic number, because the mean of its divisors is an integer number (13707284).

Almost surely, 2^81855129 is an apocalyptic number.

It is an amenable number.

81855129 is a deficient number, since it is larger than the sum of its proper divisors (27803143).

81855129 is a wasteful number, since it uses less digits than its factorization.

81855129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129527.

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

The square root of 81855129 is about 9047.3824391367. The cubic root of 81855129 is about 434.1921484171.

The spelling of 81855129 in words is "eighty-one million, eight hundred fifty-five thousand, one hundred twenty-nine".