21020100239 has 2 divisors, whose sum is σ = 21020100240. Its totient is φ = 21020100238.

The previous prime is 21020100163. The next prime is 21020100259. The reversal of 21020100239 is 93200102012.

It is an a-pointer prime, because the next prime (21020100259) can be obtained adding 21020100239 to its sum of digits (20).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21020100239 - 2²⁸ = 20751664783 is a prime.

It is a super-2 number, since 2×21020100239² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21020100239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020100259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510050119 + 10510050120.

It is an arithmetic number, because the mean of its divisors is an integer number (10510050120).

Almost surely, 2^21020100239 is an apocalyptic number.

21020100239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020100239 is an equidigital number, since it uses as much as digits as its factorization.

21020100239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

The spelling of 21020100239 in words is "twenty-one billion, twenty million, one hundred thousand, two hundred thirty-nine".