21121143 has 4 divisors (see below), whose sum is σ = 28161528. Its totient is φ = 14080760.

The previous prime is 21121129. The next prime is 21121171. The reversal of 21121143 is 34112112.

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 21121143 - 2¹⁰ = 21120119 is a prime.

It is a super-2 number, since 2×21121143² = 892205363252898, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123143) 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 3 ways as a sum of consecutive naturals, for example, 3520188 + ... + 3520193.

It is an arithmetic number, because the mean of its divisors is an integer number (7040382).

Almost surely, 2^21121143 is an apocalyptic number.

21121143 is a deficient number, since it is larger than the sum of its proper divisors (7040385).

21121143 is an equidigital number, since it uses as much as digits as its factorization.

21121143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7040384.

The product of its digits is 48, while the sum is 15.

The square root of 21121143 is about 4595.7744722734. The cubic root of 21121143 is about 276.4219156091.

Adding to 21121143 its reverse (34112112), we get a palindrome (55233255).

The spelling of 21121143 in words is "twenty-one million, one hundred twenty-one thousand, one hundred forty-three".