21251235029 has 2 divisors, whose sum is σ = 21251235030. Its totient is φ = 21251235028.

The previous prime is 21251234947. The next prime is 21251235073. The reversal of 21251235029 is 92053215212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16121380900 + 5129854129 = 126970^2 + 71623^2 .

It is a cyclic number.

It is not a de Polignac number, because 21251235029 - 2³² = 16956267733 is a prime.

It is a super-2 number, since 2×21251235029² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21251234986 and 21251235004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21251235079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625617514 + 10625617515.

It is an arithmetic number, because the mean of its divisors is an integer number (10625617515).

Almost surely, 2^21251235029 is an apocalyptic number.

It is an amenable number.

21251235029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251235029 is an equidigital number, since it uses as much as digits as its factorization.

21251235029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21251235029 in words is "twenty-one billion, two hundred fifty-one million, two hundred thirty-five thousand, twenty-nine".