21648407 has 8 divisors (see below), whose sum is σ = 23675520. Its totient is φ = 19631160.

The previous prime is 21648401. The next prime is 21648421. The reversal of 21648407 is 70484612.

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 21648407 - 2⁶ = 21648343 is a prime.

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 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, 2588 + ... + 7070.

It is an arithmetic number, because the mean of its divisors is an integer number (2959440).

Almost surely, 2^21648407 is an apocalyptic number.

21648407 is a deficient number, since it is larger than the sum of its proper divisors (2027113).

21648407 is a wasteful number, since it uses less digits than its factorization.

21648407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4933.

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 21648407 is about 4652.7848650029. The cubic root of 21648407 is about 278.7032168265.

The spelling of 21648407 in words is "twenty-one million, six hundred forty-eight thousand, four hundred seven".