21880111 has 4 divisors (see below), whose sum is σ = 23869224. Its totient is φ = 19891000.

The previous prime is 21880099. The next prime is 21880121. The reversal of 21880111 is 11108812.

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 21880111 - 2¹⁹ = 21355823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880121) 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, 994540 + ... + 994561.

It is an arithmetic number, because the mean of its divisors is an integer number (5967306).

Almost surely, 2^21880111 is an apocalyptic number.

21880111 is a deficient number, since it is larger than the sum of its proper divisors (1989113).

21880111 is a wasteful number, since it uses less digits than its factorization.

21880111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1989112.

The product of its (nonzero) digits is 128, while the sum is 22.

The square root of 21880111 is about 4677.6180904388. The cubic root of 21880111 is about 279.6940152306.

Adding to 21880111 its reverse (11108812), we get a palindrome (32988923).

It can be divided in two parts, 218801 and 11, that added together give a palindrome (218812).

The spelling of 21880111 in words is "twenty-one million, eight hundred eighty thousand, one hundred eleven".