21011123 has 8 divisors (see below), whose sum is σ = 24057600. Its totient is φ = 17975880.

The previous prime is 21011083. The next prime is 21011141. The reversal of 21011123 is 32111012.

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

It is a cyclic number.

It is not a de Polignac number, because 21011123 - 2²⁴ = 4233907 is a prime.

It is a super-2 number, since 2×21011123² = 882934579442258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21011143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1688 + ... + 6698.

It is an arithmetic number, because the mean of its divisors is an integer number (3007200).

Almost surely, 2^21011123 is an apocalyptic number.

21011123 is a deficient number, since it is larger than the sum of its proper divisors (3046477).

21011123 is an equidigital number, since it uses as much as digits as its factorization.

21011123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5617.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21011123 is about 4583.7891530916. The cubic root of 21011123 is about 275.9411193796.

Adding to 21011123 its reverse (32111012), we get a palindrome (53122135).

The spelling of 21011123 in words is "twenty-one million, eleven thousand, one hundred twenty-three".