21438807 has 8 divisors (see below), whose sum is σ = 30783984. Its totient is φ = 13193088.

The previous prime is 21438793. The next prime is 21438827. The reversal of 21438807 is 70883412.

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

It is a de Polignac number, because none of the positive numbers 2^k-21438807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21438827) 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, 274818 + ... + 274895.

It is an arithmetic number, because the mean of its divisors is an integer number (3847998).

Almost surely, 2^21438807 is an apocalyptic number.

21438807 is a deficient number, since it is larger than the sum of its proper divisors (9345177).

21438807 is a wasteful number, since it uses less digits than its factorization.

21438807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549729.

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 21438807 is about 4630.2059349450. The cubic root of 21438807 is about 277.8008295122.

The spelling of 21438807 in words is "twenty-one million, four hundred thirty-eight thousand, eight hundred seven".