21001222079 has 2 divisors, whose sum is σ = 21001222080. Its totient is φ = 21001222078.

The previous prime is 21001222061. The next prime is 21001222127. The reversal of 21001222079 is 97022210012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001222079 is a prime.

It is a super-2 number, since 2×21001222079² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001222009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500611039 + 10500611040.

It is an arithmetic number, because the mean of its divisors is an integer number (10500611040).

Almost surely, 2^21001222079 is an apocalyptic number.

21001222079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001222079 is an equidigital number, since it uses as much as digits as its factorization.

21001222079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 26.

The spelling of 21001222079 in words is "twenty-one billion, one million, two hundred twenty-two thousand, seventy-nine".