21447489 has 16 divisors (see below), whose sum is σ = 34604928. Its totient is φ = 11534592.

The previous prime is 21447427. The next prime is 21447509. The reversal of 21447489 is 98474412.

It is not a de Polignac number, because 21447489 - 2¹¹ = 21445441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21447289) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29682 + ... + 30395.

It is an arithmetic number, because the mean of its divisors is an integer number (2162808).

Almost surely, 2^21447489 is an apocalyptic number.

It is an amenable number.

21447489 is a deficient number, since it is larger than the sum of its proper divisors (13157439).

21447489 is a wasteful number, since it uses less digits than its factorization.

21447489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60104.

The product of its digits is 64512, while the sum is 39.

The square root of 21447489 is about 4631.1433793395. The cubic root of 21447489 is about 277.8383244670.

The spelling of 21447489 in words is "twenty-one million, four hundred forty-seven thousand, four hundred eighty-nine".