21210423 has 8 divisors (see below), whose sum is σ = 30456048. Its totient is φ = 13052544.

The previous prime is 21210389. The next prime is 21210433. The reversal of 21210423 is 32401212.

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

It is not a de Polignac number, because 21210423 - 2²² = 17016119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 271890 + ... + 271967.

It is an arithmetic number, because the mean of its divisors is an integer number (3807006).

Almost surely, 2^21210423 is an apocalyptic number.

21210423 is a deficient number, since it is larger than the sum of its proper divisors (9245625).

21210423 is a wasteful number, since it uses less digits than its factorization.

21210423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 543873.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21210423 is about 4605.4774996736. The cubic root of 21210423 is about 276.8108506374.

Adding to 21210423 its reverse (32401212), we get a palindrome (53611635).

The spelling of 21210423 in words is "twenty-one million, two hundred ten thousand, four hundred twenty-three".