82121645 has 16 divisors (see below), whose sum is σ = 106317360. Its totient is φ = 60662784.

The previous prime is 82121639. The next prime is 82121719. The reversal of 82121645 is 54612128.

It can be written as a sum of positive squares in 8 ways, for example, as 23843689 + 58277956 = 4883^2 + 7634^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82121645 is a prime.

It is a super-3 number, since 3×82121645³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4610 + ... + 13619.

It is an arithmetic number, because the mean of its divisors is an integer number (6644835).

Almost surely, 2^82121645 is an apocalyptic number.

82121645 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

82121645 is a deficient number, since it is larger than the sum of its proper divisors (24195715).

82121645 is a wasteful number, since it uses less digits than its factorization.

82121645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18304.

The product of its digits is 3840, while the sum is 29.

The square root of 82121645 is about 9062.0993704549. The cubic root of 82121645 is about 434.6628735095.

The spelling of 82121645 in words is "eighty-two million, one hundred twenty-one thousand, six hundred forty-five".