82171989 has 10 divisors (see below), whose sum is σ = 122750870. Its totient is φ = 54781272.

The previous prime is 82171967. The next prime is 82172021. The reversal of 82171989 is 98917128.

It can be written as a sum of positive squares in only one way, i.e., 64883025 + 17288964 = 8055^2 + 4158^2 .

It is not a de Polignac number, because 82171989 - 2⁹ = 82171477 is a prime.

It is a super-2 number, since 2×82171989² = 13504471552432242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82170989) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 507154 + ... + 507315.

It is an arithmetic number, because the mean of its divisors is an integer number (12275087).

Almost surely, 2^82171989 is an apocalyptic number.

It is an amenable number.

82171989 is a deficient number, since it is larger than the sum of its proper divisors (40578881).

82171989 is a wasteful number, since it uses less digits than its factorization.

82171989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1014481 (or 1014472 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 82171989 is about 9064.8766676663. The cubic root of 82171989 is about 434.7516775333.

The spelling of 82171989 in words is "eighty-two million, one hundred seventy-one thousand, nine hundred eighty-nine".