21281983829 has 2 divisors, whose sum is σ = 21281983830. Its totient is φ = 21281983828.

The previous prime is 21281983799. The next prime is 21281983889. The reversal of 21281983829 is 92838918212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12123111025 + 9158872804 = 110105^2 + 95702^2 .

It is a cyclic number.

It is not a de Polignac number, because 21281983829 - 2⁸ = 21281983573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21281983889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10640991914 + 10640991915.

It is an arithmetic number, because the mean of its divisors is an integer number (10640991915).

Almost surely, 2^21281983829 is an apocalyptic number.

It is an amenable number.

21281983829 is a deficient number, since it is larger than the sum of its proper divisors (1).

21281983829 is an equidigital number, since it uses as much as digits as its factorization.

21281983829 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 53.

The spelling of 21281983829 in words is "twenty-one billion, two hundred eighty-one million, nine hundred eighty-three thousand, eight hundred twenty-nine".