66801798 has 144 divisors (see below), whose sum is σ = 182463840. Its totient is φ = 17563392.

The previous prime is 66801797. The next prime is 66801809. The reversal of 66801798 is 89710866.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66801793) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 750538 + ... + 750626.

It is an arithmetic number, because the mean of its divisors is an integer number (1267110).

Almost surely, 2^66801798 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66801798, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91231920).

66801798 is an abundant number, since it is smaller than the sum of its proper divisors (115662042).

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

66801798 is a wasteful number, since it uses less digits than its factorization.

66801798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 66801798 is about 8173.2366905651. The cubic root of 66801798 is about 405.7539134950.

The spelling of 66801798 in words is "sixty-six million, eight hundred one thousand, seven hundred ninety-eight".