16663777640 has 16 divisors (see below), whose sum is σ = 37493499780. Its totient is φ = 6665511040.

The previous prime is 16663777607. The next prime is 16663777643. The reversal of 16663777640 is 4677736661.

It can be written as a sum of positive squares in 2 ways, for example, as 16290437956 + 373339684 = 127634^2 + 19322^2 .

It is not an unprimeable number, because it can be changed into a prime (16663777643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208297181 + ... + 208297260.

Almost surely, 2^16663777640 is an apocalyptic number.

16663777640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16663777640 is an abundant number, since it is smaller than the sum of its proper divisors (20829722140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16663777640 is a wasteful number, since it uses less digits than its factorization.

16663777640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416594452 (or 416594448 counting only the distinct ones).

The product of its (nonzero) digits is 5334336, while the sum is 53.

The spelling of 16663777640 in words is "sixteen billion, six hundred sixty-three million, seven hundred seventy-seven thousand, six hundred forty".