21753753181 has 2 divisors, whose sum is σ = 21753753182. Its totient is φ = 21753753180.

The previous prime is 21753753157. The next prime is 21753753251. The reversal of 21753753181 is 18135735712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21617820900 + 135932281 = 147030^2 + 11659^2 .

It is a cyclic number.

It is not a de Polignac number, because 21753753181 - 2⁵ = 21753753149 is a prime.

It is a super-2 number, since 2×21753753181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21753753481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10876876590 + 10876876591.

It is an arithmetic number, because the mean of its divisors is an integer number (10876876591).

Almost surely, 2^21753753181 is an apocalyptic number.

It is an amenable number.

21753753181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21753753181 is an equidigital number, since it uses as much as digits as its factorization.

21753753181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 176400, while the sum is 43.

The spelling of 21753753181 in words is "twenty-one billion, seven hundred fifty-three million, seven hundred fifty-three thousand, one hundred eighty-one".