21742743619681 has 8 divisors (see below), whose sum is σ = 25705706742720. Its totient is φ = 17993994719568.

The previous prime is 21742743619643. The next prime is 21742743619697. The reversal of 21742743619681 is 18691634724712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21742743619681 - 2¹¹ = 21742743617633 is a prime.

It is a super-2 number, since 2×21742743619681² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21742743619601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53553555511 + ... + 53553555916.

It is an arithmetic number, because the mean of its divisors is an integer number (3213213342840).

Almost surely, 2^{21742743619681} is an apocalyptic number.

It is an amenable number.

21742743619681 is a deficient number, since it is larger than the sum of its proper divisors (3962963123039).

21742743619681 is a wasteful number, since it uses less digits than its factorization.

21742743619681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107107111463.

The product of its digits is 24385536, while the sum is 61.

The spelling of 21742743619681 in words is "twenty-one trillion, seven hundred forty-two billion, seven hundred forty-three million, six hundred nineteen thousand, six hundred eighty-one".