21742743619679 has 4 divisors (see below), whose sum is σ = 21744133036800. Its totient is φ = 21741354202560.

The previous prime is 21742743619643. The next prime is 21742743619697. The reversal of 21742743619679 is 97691634724712.

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 21742743619679 - 2³⁶ = 21674024142943 is a prime.

It is a super-2 number, since 2×21742743619679² (a number of 27 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 (21742743619579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 694685087 + ... + 694716384.

It is an arithmetic number, because the mean of its divisors is an integer number (5436033259200).

Almost surely, 2^{21742743619679} is an apocalyptic number.

21742743619679 is a deficient number, since it is larger than the sum of its proper divisors (1389417121).

21742743619679 is a wasteful number, since it uses less digits than its factorization.

21742743619679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1389417120.

The product of its digits is 192036096, while the sum is 68.

The spelling of 21742743619679 in words is "twenty-one trillion, seven hundred forty-two billion, seven hundred forty-three million, six hundred nineteen thousand, six hundred seventy-nine".