66803404400640 has 144 divisors (see below), whose sum is σ = 231528596235300. Its totient is φ = 17814241148928.

The previous prime is 66803404400627. The next prime is 66803404400693. The reversal of 66803404400640 is 4600440430866.

66803404400640 is a `hidden beast` number, since 66 + 80 + 34 + 0 + 440 + 0 + 6 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 63842912510976 + 2960491889664 = 7990176^2 + 1720608^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 362339505 + ... + 362523824.

Almost surely, 2^{66803404400640} is an apocalyptic number.

66803404400640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66803404400640 is an abundant number, since it is smaller than the sum of its proper divisors (164725191834660).

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

66803404400640 is a wasteful number, since it uses less digits than its factorization.

66803404400640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724863362 (or 724863339 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 45.

The spelling of 66803404400640 in words is "sixty-six trillion, eight hundred three billion, four hundred four million, four hundred thousand, six hundred forty".