81571889 has 8 divisors (see below), whose sum is σ = 93297600. Its totient is φ = 69864336.

The previous prime is 81571873. The next prime is 81571901. The reversal of 81571889 is 98817518.

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

It is a cyclic number.

It is not a de Polignac number, because 81571889 - 2⁴ = 81571873 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81571489) 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, 7082 + ... + 14604.

It is an arithmetic number, because the mean of its divisors is an integer number (11662200).

Almost surely, 2^81571889 is an apocalyptic number.

It is an amenable number.

81571889 is a deficient number, since it is larger than the sum of its proper divisors (11725711).

81571889 is a wasteful number, since it uses less digits than its factorization.

81571889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9079.

The product of its digits is 161280, while the sum is 47.

The square root of 81571889 is about 9031.7157284760. The cubic root of 81571889 is about 433.6907638075.

The spelling of 81571889 in words is "eighty-one million, five hundred seventy-one thousand, eight hundred eighty-nine".