17900031681 has 81 divisors (see below), whose sum is σ = 31555389411. Its totient is φ = 9748547424.

The previous prime is 17900031671. The next prime is 17900031703. The reversal of 17900031681 is 18613000971.

The square root of 17900031681 is 133791.

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., 3085247025 + 14814784656 = 55545^2 + 121716^2 .

It is not a de Polignac number, because 17900031681 - 2⁷ = 17900031553 is a prime.

It is a super-2 number, since 2×17900031681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (17900031631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 64620915 + ... + 64621191.

Almost surely, 2^17900031681 is an apocalyptic number.

17900031681 is the 133791-st square number.

17900031681 is the 66896-th centered octagonal number.

It is an amenable number.

17900031681 is a deficient number, since it is larger than the sum of its proper divisors (13655357730).

17900031681 is an equidigital number, since it uses as much as digits as its factorization.

17900031681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620 (or 310 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

Multiplying 17900031681 by its sum of digits (36), we get a square (644401140516 = 802746²).

It can be divided in two parts, 179000 and 31681, that added together give a square (210681 = 459²).

The spelling of 17900031681 in words is "seventeen billion, nine hundred million, thirty-one thousand, six hundred eighty-one".