21648406 has 8 divisors (see below), whose sum is σ = 34970544. Its totient is φ = 9991560.

The previous prime is 21648401. The next prime is 21648421. The reversal of 21648406 is 60484612.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21648401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 416290 + ... + 416341.

It is an arithmetic number, because the mean of its divisors is an integer number (4371318).

Almost surely, 2^21648406 is an apocalyptic number.

21648406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21648406 is a deficient number, since it is larger than the sum of its proper divisors (13322138).

21648406 is a wasteful number, since it uses less digits than its factorization.

21648406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 832646.

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 21648406 is about 4652.7847575404. The cubic root of 21648406 is about 278.7032125351.

The spelling of 21648406 in words is "twenty-one million, six hundred forty-eight thousand, four hundred six".