82156221 has 16 divisors (see below), whose sum is σ = 139100800. Its totient is φ = 46946304.

The previous prime is 82156183. The next prime is 82156229. The reversal of 82156221 is 12265128.

It is a happy number.

82156221 is a `hidden beast` number, since 82 + 1 + 562 + 21 = 666.

It is not a de Polignac number, because 82156221 - 2⁶ = 82156157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82156229) 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, 217156 + ... + 217533.

It is an arithmetic number, because the mean of its divisors is an integer number (8693800).

Almost surely, 2^82156221 is an apocalyptic number.

It is an amenable number.

82156221 is a deficient number, since it is larger than the sum of its proper divisors (56944579).

82156221 is a wasteful number, since it uses less digits than its factorization.

82156221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434705 (or 434699 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 82156221 is about 9064.0068954078. The cubic root of 82156221 is about 434.7238675579.

The spelling of 82156221 in words is "eighty-two million, one hundred fifty-six thousand, two hundred twenty-one".