21915029 has 2 divisors, whose sum is σ = 21915030. Its totient is φ = 21915028.

The previous prime is 21915017. The next prime is 21915031. The reversal of 21915029 is 92051912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11662225 + 10252804 = 3415^2 + 3202^2 .

It is a cyclic number.

It is not a de Polignac number, because 21915029 - 2⁴ = 21915013 is a prime.

Together with 21915031, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21914992 and 21915010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21915059) 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, 10957514 + 10957515.

It is an arithmetic number, because the mean of its divisors is an integer number (10957515).

Almost surely, 2^21915029 is an apocalyptic number.

It is an amenable number.

21915029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21915029 is an equidigital number, since it uses as much as digits as its factorization.

21915029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 21915029 is about 4681.3490576969. The cubic root of 21915029 is about 279.8427220466.

The spelling of 21915029 in words is "twenty-one million, nine hundred fifteen thousand, twenty-nine".