21745660741 has 4 divisors (see below), whose sum is σ = 24852183712. Its totient is φ = 18639137772.

The previous prime is 21745660711. The next prime is 21745660777. The reversal of 21745660741 is 14706654712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21745660741 - 2¹⁹ = 21745136453 is a prime.

It is a super-2 number, since 2×21745660741² (a number of 21 digits) 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 (21745660711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1553261475 + ... + 1553261488.

It is an arithmetic number, because the mean of its divisors is an integer number (6213045928).

Almost surely, 2^21745660741 is an apocalyptic number.

It is an amenable number.

21745660741 is a deficient number, since it is larger than the sum of its proper divisors (3106522971).

21745660741 is an equidigital number, since it uses as much as digits as its factorization.

21745660741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3106522970.

The product of its (nonzero) digits is 282240, while the sum is 43.

The spelling of 21745660741 in words is "twenty-one billion, seven hundred forty-five million, six hundred sixty thousand, seven hundred forty-one".