21869669 has 2 divisors, whose sum is σ = 21869670. Its totient is φ = 21869668.

The previous prime is 21869641. The next prime is 21869677. The reversal of 21869669 is 96696812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11222500 + 10647169 = 3350^2 + 3263^2 .

It is a cyclic number.

It is not a de Polignac number, because 21869669 - 2¹² = 21865573 is a prime.

It is a super-2 number, since 2×21869669² = 956564844339122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21869609) 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, 10934834 + 10934835.

It is an arithmetic number, because the mean of its divisors is an integer number (10934835).

Almost surely, 2^21869669 is an apocalyptic number.

It is an amenable number.

21869669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21869669 is an equidigital number, since it uses as much as digits as its factorization.

21869669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 47.

The square root of 21869669 is about 4676.5017908689. The cubic root of 21869669 is about 279.6495147003.

The spelling of 21869669 in words is "twenty-one million, eight hundred sixty-nine thousand, six hundred sixty-nine".