21489771 has 8 divisors (see below), whose sum is σ = 28699024. Its totient is φ = 14303520.

The previous prime is 21489761. The next prime is 21489791. The reversal of 21489771 is 17798412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21489771 - 2⁵ = 21489739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21489701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3436 + ... + 7401.

It is an arithmetic number, because the mean of its divisors is an integer number (3587378).

Almost surely, 2^21489771 is an apocalyptic number.

21489771 is a deficient number, since it is larger than the sum of its proper divisors (7209253).

21489771 is a wasteful number, since it uses less digits than its factorization.

21489771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11501.

The product of its digits is 28224, while the sum is 39.

The square root of 21489771 is about 4635.7060950841. The cubic root of 21489771 is about 278.0207832572.

The spelling of 21489771 in words is "twenty-one million, four hundred eighty-nine thousand, seven hundred seventy-one".