66388500 has 72 divisors (see below), whose sum is σ = 209447784. Its totient is φ = 17702400.

The previous prime is 66388499. The next prime is 66388501. The reversal of 66388500 is 588366.

It is an interprime number because it is at equal distance from previous prime (66388499) and next prime (66388501).

It can be written as a sum of positive squares in 4 ways, for example, as 3090564 + 63297936 = 1758^2 + 7956^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66388501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2877 + ... + 11876.

It is an arithmetic number, because the mean of its divisors is an integer number (2908997).

Almost surely, 2^66388500 is an apocalyptic number.

66388500 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66388500 is an abundant number, since it is smaller than the sum of its proper divisors (143059284).

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

66388500 is a wasteful number, since it uses less digits than its factorization.

66388500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14778 (or 14763 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 66388500 is about 8147.9138434326. The cubic root of 66388500 is about 404.9153915621.

The spelling of 66388500 in words is "sixty-six million, three hundred eighty-eight thousand, five hundred".