21469989 has 4 divisors (see below), whose sum is σ = 28626656. Its totient is φ = 14313324.

The previous prime is 21469969. The next prime is 21469999. The reversal of 21469989 is 98996412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21469989 - 2⁸ = 21469733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21469919) 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 in 3 ways as a sum of consecutive naturals, for example, 3578329 + ... + 3578334.

It is an arithmetic number, because the mean of its divisors is an integer number (7156664).

Almost surely, 2^21469989 is an apocalyptic number.

It is an amenable number.

21469989 is a deficient number, since it is larger than the sum of its proper divisors (7156667).

21469989 is an equidigital number, since it uses as much as digits as its factorization.

21469989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7156666.

The product of its digits is 279936, while the sum is 48.

The square root of 21469989 is about 4633.5719482922. The cubic root of 21469989 is about 277.9354481524.

The spelling of 21469989 in words is "twenty-one million, four hundred sixty-nine thousand, nine hundred eighty-nine".