27726661781 has 16 divisors (see below), whose sum is σ = 34166678784. Its totient is φ = 21910863744.

The previous prime is 27726661747. The next prime is 27726661799. The reversal of 27726661781 is 18716662772.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-27726661781 is a prime.

It is a super-3 number, since 3×27726661781³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27726661381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110216 + ... + 260001.

It is an arithmetic number, because the mean of its divisors is an integer number (2135417424).

Almost surely, 2^27726661781 is an apocalyptic number.

It is an amenable number.

27726661781 is a deficient number, since it is larger than the sum of its proper divisors (6440017003).

27726661781 is a wasteful number, since it uses less digits than its factorization.

27726661781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371060.

The product of its digits is 2370816, while the sum is 53.

Subtracting from 27726661781 its reverse (18716662772), we obtain a palindrome (9009999009).

The spelling of 27726661781 in words is "twenty-seven billion, seven hundred twenty-six million, six hundred sixty-one thousand, seven hundred eighty-one".