19666066690 has 16 divisors (see below), whose sum is σ = 35406490680. Its totient is φ = 7864744320.

The previous prime is 19666066681. The next prime is 19666066691. The reversal of 19666066690 is 9666066691.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 11559045169 + 8107021521 = 107513^2 + 90039^2 .

It is a super-2 number, since 2×19666066690² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19666066691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160641 + ... + 255220.

Almost surely, 2^19666066690 is an apocalyptic number.

19666066690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19666066690 is a deficient number, since it is larger than the sum of its proper divisors (15740423990).

19666066690 is a wasteful number, since it uses less digits than its factorization.

19666066690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420597.

The product of its (nonzero) digits is 3779136, while the sum is 55.

Subtracting from 19666066690 its reverse (9666066691), we obtain a palindrome (9999999999).

The spelling of 19666066690 in words is "nineteen billion, six hundred sixty-six million, sixty-six thousand, six hundred ninety".