102100200021 has 24 divisors (see below), whose sum is σ = 153144654936. Its totient is φ = 65496936960.

The previous prime is 102100200017. The next prime is 102100200029. The reversal of 102100200021 is 120002001201.

It can be written as a sum of positive squares in 4 ways, for example, as 1347917796 + 100752282225 = 36714^2 + 317415^2 .

It is not a de Polignac number, because 102100200021 - 2² = 102100200017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 102100199976 and 102100200012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102100200029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1868230 + ... + 1922103.

It is an arithmetic number, because the mean of its divisors is an integer number (6381027289).

Almost surely, 2^102100200021 is an apocalyptic number.

It is an amenable number.

102100200021 is a deficient number, since it is larger than the sum of its proper divisors (51044454915).

102100200021 is a wasteful number, since it uses less digits than its factorization.

102100200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3790453 (or 3790450 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 102100200021 its reverse (120002001201), we get a palindrome (222102201222).

The spelling of 102100200021 in words is "one hundred two billion, one hundred million, two hundred thousand, twenty-one".