21778986281 has 8 divisors (see below), whose sum is σ = 24474045120. Its totient is φ = 19229606352.

The previous prime is 21778986269. The next prime is 21778986293. The reversal of 21778986281 is 18268987712.

It is an interprime number because it is at equal distance from previous prime (21778986269) and next prime (21778986293).

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

It is a cyclic number.

It is not a de Polignac number, because 21778986281 - 2¹⁰ = 21778985257 is a prime.

It is a super-2 number, since 2×21778986281² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21778986281.

It is not an unprimeable number, because it can be changed into a prime (21778986241) 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, 36419411 + ... + 36420008.

It is an arithmetic number, because the mean of its divisors is an integer number (3059255640).

Almost surely, 2^21778986281 is an apocalyptic number.

It is an amenable number.

21778986281 is a deficient number, since it is larger than the sum of its proper divisors (2695058839).

21778986281 is a wasteful number, since it uses less digits than its factorization.

21778986281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72839455.

The product of its digits is 5419008, while the sum is 59.

The spelling of 21778986281 in words is "twenty-one billion, seven hundred seventy-eight million, nine hundred eighty-six thousand, two hundred eighty-one".