66356820 has 60 divisors (see below), whose sum is σ = 208168884. Its totient is φ = 17694720.

The previous prime is 66356791. The next prime is 66356839. The reversal of 66356820 is 2865366.

66356820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 44116164 + 22240656 = 6642^2 + 4716^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 18861 + ... + 22100.

Almost surely, 2^66356820 is an apocalyptic number.

66356820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66356820 is an abundant number, since it is smaller than the sum of its proper divisors (141812064).

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

66356820 is a wasteful number, since it uses less digits than its factorization.

66356820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40982 (or 40971 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 66356820 is about 8145.9695555532. The cubic root of 66356820 is about 404.8509739769.

It can be divided in two parts, 66356 and 820, that added together give a palindrome (67176).

The spelling of 66356820 in words is "sixty-six million, three hundred fifty-six thousand, eight hundred twenty".