21797111 has 24 divisors (see below), whose sum is σ = 27184896. Its totient is φ = 17364480.

The previous prime is 21797093. The next prime is 21797119. The reversal of 21797111 is 11179712.

It is not a de Polignac number, because 21797111 - 2¹⁴ = 21780727 is a prime.

It is a super-2 number, since 2×21797111² = 950228095892642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797119) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 114026 + ... + 114216.

It is an arithmetic number, because the mean of its divisors is an integer number (1132704).

Almost surely, 2^21797111 is an apocalyptic number.

21797111 is a deficient number, since it is larger than the sum of its proper divisors (5387785).

21797111 is a wasteful number, since it uses less digits than its factorization.

21797111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359 (or 352 counting only the distinct ones).

The product of its digits is 882, while the sum is 29.

The square root of 21797111 is about 4668.7376238122. The cubic root of 21797111 is about 279.3399033864.

It can be divided in two parts, 2179711 and 1, that added together give a palindrome (2179712).

The spelling of 21797111 in words is "twenty-one million, seven hundred ninety-seven thousand, one hundred eleven".