82121661 has 16 divisors (see below), whose sum is σ = 126952320. Its totient is φ = 52367040.

The previous prime is 82121639. The next prime is 82121719. The reversal of 82121661 is 16612128.

It is not a de Polignac number, because 82121661 - 2⁶ = 82121597 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82121261) 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, 65500 + ... + 66741.

It is an arithmetic number, because the mean of its divisors is an integer number (7934520).

Almost surely, 2^82121661 is an apocalyptic number.

It is an amenable number.

82121661 is a deficient number, since it is larger than the sum of its proper divisors (44830659).

82121661 is a wasteful number, since it uses less digits than its factorization.

82121661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132273 (or 132267 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 82121661 is about 9062.1002532526. The cubic root of 82121661 is about 434.6629017384.

Adding to 82121661 its reverse (16612128), we get a palindrome (98733789).

The spelling of 82121661 in words is "eighty-two million, one hundred twenty-one thousand, six hundred sixty-one".