21923213 has 8 divisors (see below), whose sum is σ = 23660448. Its totient is φ = 20193264.

The previous prime is 21923179. The next prime is 21923227. The reversal of 21923213 is 31232912.

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-21923213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21923273) 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, 5570 + ... + 8652.

It is an arithmetic number, because the mean of its divisors is an integer number (2957556).

Almost surely, 2^21923213 is an apocalyptic number.

It is an amenable number.

21923213 is a deficient number, since it is larger than the sum of its proper divisors (1737235).

21923213 is a wasteful number, since it uses less digits than its factorization.

21923213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3643.

The product of its digits is 648, while the sum is 23.

The square root of 21923213 is about 4682.2230831091. The cubic root of 21923213 is about 279.8775527527.

It can be divided in two parts, 219 and 23213, that added together give a palindrome (23432).

The spelling of 21923213 in words is "twenty-one million, nine hundred twenty-three thousand, two hundred thirteen".