21121123 has 4 divisors (see below), whose sum is σ = 22363560. Its totient is φ = 19878688.

The previous prime is 21121099. The next prime is 21121129. The reversal of 21121123 is 32112112.

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

It is a cyclic number.

It is not a de Polignac number, because 21121123 - 2⁵ = 21121091 is a prime.

It is a super-2 number, since 2×21121123² = 892203673562258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121129) 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, 621193 + ... + 621226.

It is an arithmetic number, because the mean of its divisors is an integer number (5590890).

Almost surely, 2^21121123 is an apocalyptic number.

21121123 is a deficient number, since it is larger than the sum of its proper divisors (1242437).

21121123 is a wasteful number, since it uses less digits than its factorization.

21121123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1242436.

The product of its digits is 24, while the sum is 13.

The square root of 21121123 is about 4595.7722963611. The cubic root of 21121123 is about 276.4218283594.

Adding to 21121123 its reverse (32112112), we get a palindrome (53233235).

It can be divided in two parts, 2112112 and 3, that multiplied together give a palindrome (6336336).

The spelling of 21121123 in words is "twenty-one million, one hundred twenty-one thousand, one hundred twenty-three".