21690135229 has 6 divisors (see below), whose sum is σ = 25231381854. Its totient is φ = 18591544440.

The previous prime is 21690135221. The next prime is 21690135239. The reversal of 21690135229 is 92253109612.

It can be written as a sum of positive squares in only one way, i.e., 20771439129 + 918696100 = 144123^2 + 30310^2 .

It is not a de Polignac number, because 21690135229 - 2³ = 21690135221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21690135191 and 21690135200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690135221) 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, 221327862 + ... + 221327959.

It is an arithmetic number, because the mean of its divisors is an integer number (4205230309).

Almost surely, 2^21690135229 is an apocalyptic number.

It is an amenable number.

21690135229 is a deficient number, since it is larger than the sum of its proper divisors (3541246625).

21690135229 is an equidigital number, since it uses as much as digits as its factorization.

21690135229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 442655835 (or 442655828 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 40.

The spelling of 21690135229 in words is "twenty-one billion, six hundred ninety million, one hundred thirty-five thousand, two hundred twenty-nine".