21123232101 has 6 divisors (see below), whose sum is σ = 30511335270. Its totient is φ = 14082154728.

The previous prime is 21123232099. The next prime is 21123232133. The reversal of 21123232101 is 10123232112.

It can be written as a sum of positive squares in only one way, i.e., 11983680900 + 9139551201 = 109470^2 + 95601^2 .

It is not a de Polignac number, because 21123232101 - 2¹ = 21123232099 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123232171) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1173512886 + ... + 1173512903.

It is an arithmetic number, because the mean of its divisors is an integer number (5085222545).

Almost surely, 2^21123232101 is an apocalyptic number.

It is an amenable number.

21123232101 is a deficient number, since it is larger than the sum of its proper divisors (9388103169).

21123232101 is a wasteful number, since it uses less digits than its factorization.

21123232101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2347025795 (or 2347025792 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21123232101 its reverse (10123232112), we get a palindrome (31246464213).

The spelling of 21123232101 in words is "twenty-one billion, one hundred twenty-three million, two hundred thirty-two thousand, one hundred one".