21132123109 has 2 divisors, whose sum is σ = 21132123110. Its totient is φ = 21132123108.

The previous prime is 21132123097. The next prime is 21132123163. The reversal of 21132123109 is 90132123112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17990856900 + 3141266209 = 134130^2 + 56047^2 .

It is a cyclic number.

It is not a de Polignac number, because 21132123109 - 2¹⁵ = 21132090341 is a prime.

It is a super-3 number, since 3×21132123109³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21132123169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10566061554 + 10566061555.

It is an arithmetic number, because the mean of its divisors is an integer number (10566061555).

Almost surely, 2^21132123109 is an apocalyptic number.

It is an amenable number.

21132123109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21132123109 is an equidigital number, since it uses as much as digits as its factorization.

21132123109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The spelling of 21132123109 in words is "twenty-one billion, one hundred thirty-two million, one hundred twenty-three thousand, one hundred nine".