21648169 has 8 divisors (see below), whose sum is σ = 22204448. Its totient is φ = 21098880.

The previous prime is 21648161. The next prime is 21648173. The reversal of 21648169 is 96184612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21648169 - 2³ = 21648161 is a prime.

It is a super-2 number, since 2×21648169² = 937286442105122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21648161) 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 7 ways as a sum of consecutive naturals, for example, 4834 + ... + 8164.

It is an arithmetic number, because the mean of its divisors is an integer number (2775556).

Almost surely, 2^21648169 is an apocalyptic number.

It is an amenable number.

21648169 is a deficient number, since it is larger than the sum of its proper divisors (556279).

21648169 is an equidigital number, since it uses as much as digits as its factorization.

21648169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3495.

The product of its digits is 20736, while the sum is 37.

The square root of 21648169 is about 4652.7592888522. The cubic root of 21648169 is about 278.7021954794.

The spelling of 21648169 in words is "twenty-one million, six hundred forty-eight thousand, one hundred sixty-nine".