66651588 has 18 divisors (see below), whose sum is σ = 168480494. Its totient is φ = 22217184.

The previous prime is 66651583. The next prime is 66651619. The reversal of 66651588 is 88515666.

66651588 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 only one way, i.e., 47361924 + 19289664 = 6882^2 + 4392^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (66651583) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 925681 + ... + 925752.

Almost surely, 2^66651588 is an apocalyptic number.

It is an amenable number.

66651588 is an abundant number, since it is smaller than the sum of its proper divisors (101828906).

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

66651588 is a wasteful number, since it uses less digits than its factorization.

66651588 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1851443 (or 1851438 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The square root of 66651588 is about 8164.0423810757. The cubic root of 66651588 is about 405.4495602343.

The spelling of 66651588 in words is "sixty-six million, six hundred fifty-one thousand, five hundred eighty-eight".