17727964990681 has 9 divisors (see below), whose sum is σ = 19486161187423. Its totient is φ = 16116289705120.

The previous prime is 17727964990649. The next prime is 17727964990849. The reversal of 17727964990681 is 18609946972771.

The square root of 17727964990681 is 4210459.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7229328165081 + 10498636825600 = 2688741^2 + 3240160^2 .

It is not a de Polignac number, because 17727964990681 - 2⁵ = 17727964990649 is a prime.

It is a super-2 number, since 2×17727964990681² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 17727964990598 and 17727964990607.

It is not an unprimeable number, because it can be changed into a prime (17727964990621) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 46123665 + ... + 46506433.

Almost surely, 2^{17727964990681} is an apocalyptic number.

17727964990681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

17727964990681 is the 4210459-th square number.

17727964990681 is the 2105230-th centered octagonal number.

It is an amenable number.

17727964990681 is a deficient number, since it is larger than the sum of its proper divisors (1758196196742).

17727964990681 is an frugal number, since it uses more digits than its factorization.

17727964990681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765560 (or 382780 counting only the distinct ones).

The product of its (nonzero) digits is 576108288, while the sum is 76.

The spelling of 17727964990681 in words is "seventeen trillion, seven hundred twenty-seven billion, nine hundred sixty-four million, nine hundred ninety thousand, six hundred eighty-one".