1662915990681 has 81 divisors (see below), whose sum is σ = 2761611453237. Its totient is φ = 963441871920.

The previous prime is 1662915990667. The next prime is 1662915990683. The reversal of 1662915990681 is 1860995192661.

The square root of 1662915990681 is 1289541.

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

1662915990681 is a `hidden beast` number, since 16 + 6 + 29 + 1 + 599 + 0 + 6 + 8 + 1 = 666.

It is not a de Polignac number, because 1662915990681 - 2¹⁹ = 1662915466393 is a prime.

It is a super-2 number, since 2×1662915990681² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1662915990683) 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, 978760770 + ... + 978762468.

Almost surely, 2^{1662915990681} is an apocalyptic number.

1662915990681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1662915990681 is the 1289541-st square number.

1662915990681 is the 644771-st centered octagonal number.

It is an amenable number.

1662915990681 is a deficient number, since it is larger than the sum of its proper divisors (1098695462556).

1662915990681 is an equidigital number, since it uses as much as digits as its factorization.

1662915990681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3472 (or 1736 counting only the distinct ones).

The product of its (nonzero) digits is 12597120, while the sum is 63.

The spelling of 1662915990681 in words is "one trillion, six hundred sixty-two billion, nine hundred fifteen million, nine hundred ninety thousand, six hundred eighty-one".