21578181782681 has 8 divisors (see below), whose sum is σ = 21581079858240. Its totient is φ = 21575283932592.

The previous prime is 21578181782671. The next prime is 21578181782701. The reversal of 21578181782681 is 18628718187512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21578181782681 is a prime.

It is a super-2 number, since 2×21578181782681² (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 (21578181782671) 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, 270319331 + ... + 270399143.

It is an arithmetic number, because the mean of its divisors is an integer number (2697634982280).

Almost surely, 2^{21578181782681} is an apocalyptic number.

It is an amenable number.

21578181782681 is a deficient number, since it is larger than the sum of its proper divisors (2898075559).

21578181782681 is a wasteful number, since it uses less digits than its factorization.

21578181782681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112735.

The product of its digits is 24084480, while the sum is 65.

The spelling of 21578181782681 in words is "twenty-one trillion, five hundred seventy-eight billion, one hundred eighty-one million, seven hundred eighty-two thousand, six hundred eighty-one".