21101212079 has 2 divisors, whose sum is σ = 21101212080. Its totient is φ = 21101212078.

The previous prime is 21101212061. The next prime is 21101212103. The reversal of 21101212079 is 97021210112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21101212079 - 2¹² = 21101207983 is a prime.

It is a super-2 number, since 2×21101212079² (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 (21101218079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550606039 + 10550606040.

It is an arithmetic number, because the mean of its divisors is an integer number (10550606040).

Almost surely, 2^21101212079 is an apocalyptic number.

21101212079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101212079 is an equidigital number, since it uses as much as digits as its factorization.

21101212079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 26.

The spelling of 21101212079 in words is "twenty-one billion, one hundred one million, two hundred twelve thousand, seventy-nine".