66040020 has 36 divisors (see below), whose sum is σ = 200321940. Its totient is φ = 17610624.

The previous prime is 66039997. The next prime is 66040033. The reversal of 66040020 is 2004066.

66040020 is a `hidden beast` number, since 660 + 4 + 0 + 0 + 2 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 44916804 + 21123216 = 6702^2 + 4596^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×66040020² = 8722568483200800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 66039975 and 66040002.

It is a congruent number.

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, 183265 + ... + 183624.

Almost surely, 2^66040020 is an apocalyptic number.

66040020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66040020 is an abundant number, since it is smaller than the sum of its proper divisors (134281920).

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

66040020 is a wasteful number, since it uses less digits than its factorization.

66040020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366904 (or 366899 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 66040020 is about 8126.5010921060. The cubic root of 66040020 is about 404.2056675913.

Adding to 66040020 its reverse (2004066), we get a palindrome (68044086).

The spelling of 66040020 in words is "sixty-six million, forty thousand, twenty".