21480989 has 4 divisors (see below), whose sum is σ = 21490656. Its totient is φ = 21471324.

The previous prime is 21480973. The next prime is 21480997. The reversal of 21480989 is 98908412.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21480989 - 2⁴ = 21480973 is a prime.

It is a super-2 number, since 2×21480989² = 922865776836242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21480929) 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, 362 + ... + 6564.

It is an arithmetic number, because the mean of its divisors is an integer number (5372664).

Almost surely, 2^21480989 is an apocalyptic number.

It is an amenable number.

21480989 is a deficient number, since it is larger than the sum of its proper divisors (9667).

21480989 is an equidigital number, since it uses as much as digits as its factorization.

21480989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9666.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 21480989 is about 4634.7587855249. The cubic root of 21480989 is about 277.9829061484.

The spelling of 21480989 in words is "twenty-one million, four hundred eighty thousand, nine hundred eighty-nine".