21424120111 has 4 divisors (see below), whose sum is σ = 22551705400. Its totient is φ = 20296534824.

The previous prime is 21424120099. The next prime is 21424120153. The reversal of 21424120111 is 11102142412.

It is a happy number.

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 21424120111 - 2²¹ = 21422022959 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1127585269 = 21424120111 / (2 + 1 + 4 + 2 + 4 + 1 + 2 + 0 + 1 + 1 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424130111) 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, 563792616 + ... + 563792653.

It is an arithmetic number, because the mean of its divisors is an integer number (5637926350).

Almost surely, 2^21424120111 is an apocalyptic number.

21424120111 is a deficient number, since it is larger than the sum of its proper divisors (1127585289).

21424120111 is a wasteful number, since it uses less digits than its factorization.

21424120111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1127585288.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21424120111 its reverse (11102142412), we get a palindrome (32526262523).

The spelling of 21424120111 in words is "twenty-one billion, four hundred twenty-four million, one hundred twenty thousand, one hundred eleven".