21534489 has 18 divisors (see below), whose sum is σ = 31607550. Its totient is φ = 14128128.

The previous prime is 21534479. The next prime is 21534503. The reversal of 21534489 is 98443512.

It can be written as a sum of positive squares in 3 ways, for example, as 5253264 + 16281225 = 2292^2 + 4035^2 .

It is not a de Polignac number, because 21534489 - 2⁹ = 21533977 is a prime.

It is a super-2 number, since 2×21534489² = 927468432982242, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21534479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 47737 + ... + 48185.

It is an arithmetic number, because the mean of its divisors is an integer number (1755975).

Almost surely, 2^21534489 is an apocalyptic number.

It is an amenable number.

21534489 is a deficient number, since it is larger than the sum of its proper divisors (10073061).

21534489 is an equidigital number, since it uses as much as digits as its factorization.

21534489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601 (or 525 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21534489 is about 4640.5268019913. The cubic root of 21534489 is about 278.2134938532.

The spelling of 21534489 in words is "twenty-one million, five hundred thirty-four thousand, four hundred eighty-nine".