21123393 has 8 divisors (see below), whose sum is σ = 28215648. Its totient is φ = 14056704.

The previous prime is 21123391. The next prime is 21123457. The reversal of 21123393 is 39332112.

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

It is not a de Polignac number, because 21123393 - 2¹ = 21123391 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21123391) 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, 4371 + ... + 7832.

It is an arithmetic number, because the mean of its divisors is an integer number (3526956).

Almost surely, 2^21123393 is an apocalyptic number.

It is an amenable number.

21123393 is a deficient number, since it is larger than the sum of its proper divisors (7092255).

21123393 is a wasteful number, since it uses less digits than its factorization.

21123393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12783.

The product of its digits is 972, while the sum is 24.

The square root of 21123393 is about 4596.0192558343. The cubic root of 21123393 is about 276.4317308485.

The spelling of 21123393 in words is "twenty-one million, one hundred twenty-three thousand, three hundred ninety-three".