21596724109 has 2 divisors, whose sum is σ = 21596724110. Its totient is φ = 21596724108.

The previous prime is 21596724103. The next prime is 21596724169. The reversal of 21596724109 is 90142769512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19950150025 + 1646574084 = 141245^2 + 40578^2 .

It is a cyclic number.

It is not a de Polignac number, because 21596724109 - 2²¹ = 21594626957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21596724103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10798362054 + 10798362055.

It is an arithmetic number, because the mean of its divisors is an integer number (10798362055).

Almost surely, 2^21596724109 is an apocalyptic number.

It is an amenable number.

21596724109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21596724109 is an equidigital number, since it uses as much as digits as its factorization.

21596724109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 272160, while the sum is 46.

The spelling of 21596724109 in words is "twenty-one billion, five hundred ninety-six million, seven hundred twenty-four thousand, one hundred nine".