66621594 has 16 divisors (see below), whose sum is σ = 143492832. Its totient is φ = 20498928.

The previous prime is 66621587. The next prime is 66621617. The reversal of 66621594 is 49512666.

66621594 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon 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 7 ways as a sum of consecutive naturals, for example, 426984 + ... + 427139.

It is an arithmetic number, because the mean of its divisors is an integer number (8968302).

Almost surely, 2^66621594 is an apocalyptic number.

66621594 is an abundant number, since it is smaller than the sum of its proper divisors (76871238).

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

66621594 is a wasteful number, since it uses less digits than its factorization.

66621594 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854141.

The product of its digits is 77760, while the sum is 39.

The square root of 66621594 is about 8162.2052167291. The cubic root of 66621594 is about 405.3887320823.

It can be divided in two parts, 6662 and 1594, that added together give a triangular number (8256 = T₁₂₈).

The spelling of 66621594 in words is "sixty-six million, six hundred twenty-one thousand, five hundred ninety-four".