21753131 has 2 divisors, whose sum is σ = 21753132. Its totient is φ = 21753130.

The previous prime is 21753107. The next prime is 21753163. The reversal of 21753131 is 13135712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21753131 is a prime.

It is a super-2 number, since 2×21753131² = 946397416606322, which contains 22 as substring.

It is a Chen prime.

It is equal to p_1374611 and since 21753131 and 1374611 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21753097 and 21753106.

It is not a weakly prime, because it can be changed into another prime (21753631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10876565 + 10876566.

It is an arithmetic number, because the mean of its divisors is an integer number (10876566).

Almost surely, 2^21753131 is an apocalyptic number.

21753131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21753131 is an equidigital number, since it uses as much as digits as its factorization.

21753131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 630, while the sum is 23.

The square root of 21753131 is about 4664.0251928994. The cubic root of 21753131 is about 279.1519023107.

Adding to 21753131 its reverse (13135712), we get a palindrome (34888843).

The spelling of 21753131 in words is "twenty-one million, seven hundred fifty-three thousand, one hundred thirty-one".