21962389 has 2 divisors, whose sum is σ = 21962390. Its totient is φ = 21962388.

The previous prime is 21962387. The next prime is 21962393. The reversal of 21962389 is 98326912.

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., 21622500 + 339889 = 4650^2 + 583^2 .

It is a cyclic number.

It is not a de Polignac number, because 21962389 - 2¹ = 21962387 is a prime.

Together with 21962387, 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 (21962383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10981194 + 10981195.

It is an arithmetic number, because the mean of its divisors is an integer number (10981195).

Almost surely, 2^21962389 is an apocalyptic number.

It is an amenable number.

21962389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21962389 is an equidigital number, since it uses as much as digits as its factorization.

21962389 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 21962389 is about 4686.4046987003. The cubic root of 21962389 is about 280.0441639521.

The spelling of 21962389 in words is "twenty-one million, nine hundred sixty-two thousand, three hundred eighty-nine".