66620394 has 36 divisors (see below), whose sum is σ = 149917794. Its totient is φ = 22202424.

The previous prime is 66620377. The next prime is 66620401. The reversal of 66620394 is 49302666.

It can be written as a sum of positive squares in only one way, i.e., 38900169 + 27720225 = 6237^2 + 5265^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10584 + ... + 15660.

Almost surely, 2^66620394 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66620394, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74958897).

66620394 is an abundant number, since it is smaller than the sum of its proper divisors (83297400).

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

66620394 is an frugal number, since it uses more digits than its factorization.

66620394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5103 (or 5082 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 66620394 is about 8162.1317068521. The cubic root of 66620394 is about 405.3862980897.

The spelling of 66620394 in words is "sixty-six million, six hundred twenty thousand, three hundred ninety-four".