21417489 has 6 divisors (see below), whose sum is σ = 30936386. Its totient is φ = 14278320.

The previous prime is 21417481. The next prime is 21417491. The reversal of 21417489 is 98471412.

It can be written as a sum of positive squares in only one way, i.e., 14745600 + 6671889 = 3840^2 + 2583^2 .

It is not a de Polignac number, because 21417489 - 2³ = 21417481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21417481) 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 5 ways as a sum of consecutive naturals, for example, 1189852 + ... + 1189869.

Almost surely, 2^21417489 is an apocalyptic number.

It is an amenable number.

21417489 is a deficient number, since it is larger than the sum of its proper divisors (9518897).

21417489 is a wasteful number, since it uses less digits than its factorization.

21417489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2379727 (or 2379724 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 21417489 is about 4627.9033049536. The cubic root of 21417489 is about 277.7087204985.

The spelling of 21417489 in words is "twenty-one million, four hundred seventeen thousand, four hundred eighty-nine".