21238969 has 2 divisors, whose sum is σ = 21238970. Its totient is φ = 21238968.

The previous prime is 21238963. The next prime is 21238981. The reversal of 21238969 is 96983212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21049744 + 189225 = 4588^2 + 435^2 .

It is a cyclic number.

It is not a de Polignac number, because 21238969 - 2¹¹ = 21236921 is a prime.

It is a super-2 number, since 2×21238969² = 902187608365922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21238963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10619484 + 10619485.

It is an arithmetic number, because the mean of its divisors is an integer number (10619485).

Almost surely, 2^21238969 is an apocalyptic number.

It is an amenable number.

21238969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21238969 is an equidigital number, since it uses as much as digits as its factorization.

21238969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 40.

The square root of 21238969 is about 4608.5755933911. The cubic root of 21238969 is about 276.9349767223.

The spelling of 21238969 in words is "twenty-one million, two hundred thirty-eight thousand, nine hundred sixty-nine".