1806661262641 has 9 divisors (see below), whose sum is σ = 1871148527521. Its totient is φ = 1744324963024.

The previous prime is 1806661262633. The next prime is 1806661262677. The reversal of 1806661262641 is 1462621666081.

The square root of 1806661262641 is 1344121.

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

It can be written as a sum of positive squares in 4 ways, for example, as 175830101041 + 1630831161600 = 419321^2 + 1277040^2 .

It is not a de Polignac number, because 1806661262641 - 2³ = 1806661262633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1806661262141) 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, 38956335 + ... + 39002683.

Almost surely, 2^{1806661262641} is an apocalyptic number.

1806661262641 is the 1344121-st square number.

1806661262641 is the 672061-st centered octagonal number.

It is an amenable number.

1806661262641 is a deficient number, since it is larger than the sum of its proper divisors (64487264880).

1806661262641 is an frugal number, since it uses more digits than its factorization.

1806661262641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92756 (or 46378 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 49.

Multiplying 1806661262641 by its sum of digits (49), we get a square (88526401869409 = 9408847²).

The spelling of 1806661262641 in words is "one trillion, eight hundred six billion, six hundred sixty-one million, two hundred sixty-two thousand, six hundred forty-one".