66810444 has 12 divisors (see below), whose sum is σ = 155891064. Its totient is φ = 22270144.

The previous prime is 66810439. The next prime is 66810449. The reversal of 66810444 is 44401866.

It is an interprime number because it is at equal distance from previous prime (66810439) and next prime (66810449).

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (66810449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2783757 + ... + 2783780.

It is an arithmetic number, because the mean of its divisors is an integer number (12990922).

Almost surely, 2^66810444 is an apocalyptic number.

It is an amenable number.

66810444 is an abundant number, since it is smaller than the sum of its proper divisors (89080620).

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

66810444 is a wasteful number, since it uses less digits than its factorization.

66810444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5567544 (or 5567542 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 33.

The square root of 66810444 is about 8173.7655948773. The cubic root of 66810444 is about 405.7714179988.

The spelling of 66810444 in words is "sixty-six million, eight hundred ten thousand, four hundred forty-four".