101020100021 has 2 divisors, whose sum is σ = 101020100022. Its totient is φ = 101020100020.

The previous prime is 101020100017. The next prime is 101020100023. The reversal of 101020100021 is 120001020101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79095375121 + 21924724900 = 281239^2 + 148070^2 .

It is a cyclic number.

It is not a de Polignac number, because 101020100021 - 2² = 101020100017 is a prime.

Together with 101020100023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 101020099981 and 101020100008.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101020100023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50510050010 + 50510050011.

It is an arithmetic number, because the mean of its divisors is an integer number (50510050011).

Almost surely, 2^101020100021 is an apocalyptic number.

It is an amenable number.

101020100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

101020100021 is an equidigital number, since it uses as much as digits as its factorization.

101020100021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 101020100021 its reverse (120001020101), we get a palindrome (221021120122).

The spelling of 101020100021 in words is "one hundred one billion, twenty million, one hundred thousand, twenty-one".