102100220821 has 2 divisors, whose sum is σ = 102100220822. Its totient is φ = 102100220820.

The previous prime is 102100220773. The next prime is 102100220837. The reversal of 102100220821 is 128022001201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60103915921 + 41996304900 = 245161^2 + 204930^2 .

It is a cyclic number.

It is not a de Polignac number, because 102100220821 - 2¹³ = 102100212629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102100220881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51050110410 + 51050110411.

It is an arithmetic number, because the mean of its divisors is an integer number (51050110411).

Almost surely, 2^102100220821 is an apocalyptic number.

It is an amenable number.

102100220821 is a deficient number, since it is larger than the sum of its proper divisors (1).

102100220821 is an equidigital number, since it uses as much as digits as its factorization.

102100220821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 19.

The spelling of 102100220821 in words is "one hundred two billion, one hundred million, two hundred twenty thousand, eight hundred twenty-one".