21259669 has 2 divisors, whose sum is σ = 21259670. Its totient is φ = 21259668.

The previous prime is 21259663. The next prime is 21259681. The reversal of 21259669 is 96695212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21252100 + 7569 = 4610^2 + 87^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21259669 is a prime.

It is a super-2 number, since 2×21259669² = 903947051979122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21259663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10629834 + 10629835.

It is an arithmetic number, because the mean of its divisors is an integer number (10629835).

Almost surely, 2^21259669 is an apocalyptic number.

It is an amenable number.

21259669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21259669 is an equidigital number, since it uses as much as digits as its factorization.

21259669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 40.

The square root of 21259669 is about 4610.8208596735. The cubic root of 21259669 is about 277.0249166289.

The spelling of 21259669 in words is "twenty-one million, two hundred fifty-nine thousand, six hundred sixty-nine".