21814949 has 4 divisors (see below), whose sum is σ = 23493036. Its totient is φ = 20136864.

The previous prime is 21814913. The next prime is 21814951. The reversal of 21814949 is 94941812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4592449 + 17222500 = 2143^2 + 4150^2 .

It is a cyclic number.

It is not a de Polignac number, because 21814949 - 2²⁴ = 5037733 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21814249) 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, 839024 + ... + 839049.

It is an arithmetic number, because the mean of its divisors is an integer number (5873259).

Almost surely, 2^21814949 is an apocalyptic number.

It is an amenable number.

21814949 is a deficient number, since it is larger than the sum of its proper divisors (1678087).

21814949 is a wasteful number, since it uses less digits than its factorization.

21814949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1678086.

The product of its digits is 20736, while the sum is 38.

The square root of 21814949 is about 4670.6475996375. The cubic root of 21814949 is about 279.4160833069.

The spelling of 21814949 in words is "twenty-one million, eight hundred fourteen thousand, nine hundred forty-nine".