21350869 has 2 divisors, whose sum is σ = 21350870. Its totient is φ = 21350868.

The previous prime is 21350867. The next prime is 21350897. The reversal of 21350869 is 96805312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18164644 + 3186225 = 4262^2 + 1785^2 .

It is a cyclic number.

It is not a de Polignac number, because 21350869 - 2¹ = 21350867 is a prime.

It is a super-2 number, since 2×21350869² = 911719214110322, which contains 22 as substring.

Together with 21350867, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21350863) 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, 10675434 + 10675435.

It is an arithmetic number, because the mean of its divisors is an integer number (10675435).

Almost surely, 2^21350869 is an apocalyptic number.

It is an amenable number.

21350869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21350869 is an equidigital number, since it uses as much as digits as its factorization.

21350869 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21350869 is about 4620.7000551864. The cubic root of 21350869 is about 277.4204798798.

The spelling of 21350869 in words is "twenty-one million, three hundred fifty thousand, eight hundred sixty-nine".