21838917 has 16 divisors (see below), whose sum is σ = 30098432. Its totient is φ = 14074560.

The previous prime is 21838907. The next prime is 21838919. The reversal of 21838917 is 71983812.

It is not a de Polignac number, because 21838917 - 2⁶ = 21838853 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21838919) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19548 + ... + 20634.

It is an arithmetic number, because the mean of its divisors is an integer number (1881152).

Almost surely, 2^21838917 is an apocalyptic number.

It is an amenable number.

21838917 is a deficient number, since it is larger than the sum of its proper divisors (8259515).

21838917 is a wasteful number, since it uses less digits than its factorization.

21838917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1308.

The product of its digits is 24192, while the sum is 39.

The square root of 21838917 is about 4673.2127064793. The cubic root of 21838917 is about 279.5183769758.

The spelling of 21838917 in words is "twenty-one million, eight hundred thirty-eight thousand, nine hundred seventeen".