21989269 has 2 divisors, whose sum is σ = 21989270. Its totient is φ = 21989268.

The previous prime is 21989237. The next prime is 21989281. The reversal of 21989269 is 96298912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21734244 + 255025 = 4662^2 + 505^2 .

It is a cyclic number.

It is not a de Polignac number, because 21989269 - 2⁵ = 21989237 is a prime.

It is a super-2 number, since 2×21989269² = 967055902308722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21989369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10994634 + 10994635.

It is an arithmetic number, because the mean of its divisors is an integer number (10994635).

Almost surely, 2^21989269 is an apocalyptic number.

It is an amenable number.

21989269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21989269 is an equidigital number, since it uses as much as digits as its factorization.

21989269 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 46.

The square root of 21989269 is about 4689.2716918515. The cubic root of 21989269 is about 280.1583670439.

It can be divided in two parts, 219892 and 69, that added together give a square (219961 = 469²).

The spelling of 21989269 in words is "twenty-one million, nine hundred eighty-nine thousand, two hundred sixty-nine".