102100200000021 has 12 divisors (see below), whose sum is σ = 148831076454060. Its totient is φ = 67442333944320.

The previous prime is 102100199999977. The next prime is 102100200000031. The reversal of 102100200000021 is 120000002001201.

It can be written as a sum of positive squares in 2 ways, for example, as 83150598503025 + 18949601496996 = 9118695^2 + 4353114^2 .

It is not a de Polignac number, because 102100200000021 - 2⁷ = 102100199999893 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 102100199999949 and 102100200000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102100200000031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52038836940 + ... + 52038838901.

It is an arithmetic number, because the mean of its divisors is an integer number (12402589704505).

Almost surely, 2^{102100200000021} is an apocalyptic number.

It is an amenable number.

102100200000021 is a deficient number, since it is larger than the sum of its proper divisors (46730876454039).

102100200000021 is a wasteful number, since it uses less digits than its factorization.

102100200000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104077675956 (or 104077675953 counting only the distinct ones).

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

Adding to 102100200000021 its reverse (120000002001201), we get a palindrome (222100202001222).

The spelling of 102100200000021 in words is "one hundred two trillion, one hundred billion, two hundred million, twenty-one", and thus it is an aban number.