20901199021 has 2 divisors, whose sum is σ = 20901199022. Its totient is φ = 20901199020.

The previous prime is 20901199013. The next prime is 20901199031. The reversal of 20901199021 is 12099110902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12647476521 + 8253722500 = 112461^2 + 90850^2 .

It is a cyclic number.

It is not a de Polignac number, because 20901199021 - 2³ = 20901199013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20901199031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10450599510 + 10450599511.

It is an arithmetic number, because the mean of its divisors is an integer number (10450599511).

Almost surely, 2^20901199021 is an apocalyptic number.

It is an amenable number.

20901199021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20901199021 is an equidigital number, since it uses as much as digits as its factorization.

20901199021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 34.

The spelling of 20901199021 in words is "twenty billion, nine hundred one million, one hundred ninety-nine thousand, twenty-one".