21615845029 has 2 divisors, whose sum is σ = 21615845030. Its totient is φ = 21615845028.

The previous prime is 21615844949. The next prime is 21615845087. The reversal of 21615845029 is 92054851612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10962508804 + 10653336225 = 104702^2 + 103215^2 .

It is a cyclic number.

It is not a de Polignac number, because 21615845029 - 2¹¹ = 21615842981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21615845129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10807922514 + 10807922515.

It is an arithmetic number, because the mean of its divisors is an integer number (10807922515).

Almost surely, 2^21615845029 is an apocalyptic number.

It is an amenable number.

21615845029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21615845029 is an equidigital number, since it uses as much as digits as its factorization.

21615845029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 172800, while the sum is 43.

The spelling of 21615845029 in words is "twenty-one billion, six hundred fifteen million, eight hundred forty-five thousand, twenty-nine".