21648669 has 8 divisors (see below), whose sum is σ = 32988480. Its totient is φ = 12370656.

The previous prime is 21648647. The next prime is 21648673. The reversal of 21648669 is 96684612.

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

It is not a de Polignac number, because 21648669 - 2⁷ = 21648541 is a prime.

It is a super-2 number, since 2×21648669² = 937329738943122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21648669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21648269) 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, 515424 + ... + 515465.

It is an arithmetic number, because the mean of its divisors is an integer number (4123560).

Almost surely, 2^21648669 is an apocalyptic number.

It is an amenable number.

21648669 is a deficient number, since it is larger than the sum of its proper divisors (11339811).

21648669 is a wasteful number, since it uses less digits than its factorization.

21648669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1030899.

The product of its digits is 124416, while the sum is 42.

The square root of 21648669 is about 4652.8130200987. The cubic root of 21648669 is about 278.7043411578.

The spelling of 21648669 in words is "twenty-one million, six hundred forty-eight thousand, six hundred sixty-nine".