82102508021 has 4 divisors (see below), whose sum is σ = 82124157612. Its totient is φ = 82080858432.

The previous prime is 82102508017. The next prime is 82102508023. The reversal of 82102508021 is 12080520128.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45731822500 + 36370685521 = 213850^2 + 190711^2 .

It is a cyclic number.

It is not a de Polignac number, because 82102508021 - 2² = 82102508017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82102508023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10819106 + ... + 10826691.

It is an arithmetic number, because the mean of its divisors is an integer number (20531039403).

Almost surely, 2^82102508021 is an apocalyptic number.

It is an amenable number.

82102508021 is a deficient number, since it is larger than the sum of its proper divisors (21649591).

82102508021 is a wasteful number, since it uses less digits than its factorization.

82102508021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21649590.

The product of its (nonzero) digits is 2560, while the sum is 29.

The spelling of 82102508021 in words is "eighty-two billion, one hundred two million, five hundred eight thousand, twenty-one".