21529723249 has 2 divisors, whose sum is σ = 21529723250. Its totient is φ = 21529723248.

The previous prime is 21529723181. The next prime is 21529723301. The reversal of 21529723249 is 94232792512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17049830625 + 4479892624 = 130575^2 + 66932^2 .

It is a cyclic number.

It is not a de Polignac number, because 21529723249 - 2⁹ = 21529722737 is a prime.

It is a super-2 number, since 2×21529723249² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21529723199 and 21529723208.

It is not a weakly prime, because it can be changed into another prime (21529723349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10764861624 + 10764861625.

It is an arithmetic number, because the mean of its divisors is an integer number (10764861625).

Almost surely, 2^21529723249 is an apocalyptic number.

It is an amenable number.

21529723249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21529723249 is an equidigital number, since it uses as much as digits as its factorization.

21529723249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 46.

The spelling of 21529723249 in words is "twenty-one billion, five hundred twenty-nine million, seven hundred twenty-three thousand, two hundred forty-nine".