21639224837 has 2 divisors, whose sum is σ = 21639224838. Its totient is φ = 21639224836.

The previous prime is 21639224813. The next prime is 21639224869. The reversal of 21639224837 is 73842293612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20293142116 + 1346082721 = 142454^2 + 36689^2 .

It is a cyclic number.

It is not a de Polignac number, because 21639224837 - 2¹⁰ = 21639223813 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21639224791 and 21639224800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21639224137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10819612418 + 10819612419.

It is an arithmetic number, because the mean of its divisors is an integer number (10819612419).

Almost surely, 2^21639224837 is an apocalyptic number.

It is an amenable number.

21639224837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21639224837 is an equidigital number, since it uses as much as digits as its factorization.

21639224837 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 47.

The spelling of 21639224837 in words is "twenty-one billion, six hundred thirty-nine million, two hundred twenty-four thousand, eight hundred thirty-seven".