21321123 has 8 divisors (see below), whose sum is σ = 28771008. Its totient is φ = 14042664.

The previous prime is 21321121. The next prime is 21321133. The reversal of 21321123 is 32112312.

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

It is not a de Polignac number, because 21321123 - 2¹ = 21321121 is a prime.

It is a super-2 number, since 2×21321123² = 909180571962258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21321121) 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, 42565 + ... + 43062.

It is an arithmetic number, because the mean of its divisors is an integer number (3596376).

Almost surely, 2^21321123 is an apocalyptic number.

21321123 is a deficient number, since it is larger than the sum of its proper divisors (7449885).

21321123 is an equidigital number, since it uses as much as digits as its factorization.

21321123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85713.

The product of its digits is 72, while the sum is 15.

The square root of 21321123 is about 4617.4801569687. The cubic root of 21321123 is about 277.2915860651.

Adding to 21321123 its reverse (32112312), we get a palindrome (53433435).

It can be divided in two parts, 2 and 1321123, that added together give a triangular number (1321125 = T₁₆₂₅).

The spelling of 21321123 in words is "twenty-one million, three hundred twenty-one thousand, one hundred twenty-three".