21094923 has 4 divisors (see below), whose sum is σ = 28126568. Its totient is φ = 14063280.

The previous prime is 21094907. The next prime is 21094937. The reversal of 21094923 is 32949012.

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

It is not a de Polignac number, because 21094923 - 2⁴ = 21094907 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21094903) 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, 3515818 + ... + 3515823.

It is an arithmetic number, because the mean of its divisors is an integer number (7031642).

Almost surely, 2^21094923 is an apocalyptic number.

21094923 is a deficient number, since it is larger than the sum of its proper divisors (7031645).

21094923 is an equidigital number, since it uses as much as digits as its factorization.

21094923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7031644.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 21094923 is about 4592.9209660085. The cubic root of 21094923 is about 276.3074839256.

The spelling of 21094923 in words is "twenty-one million, ninety-four thousand, nine hundred twenty-three".