66986401 has 4 divisors (see below), whose sum is σ = 67088404. Its totient is φ = 66884400.

The previous prime is 66986371. The next prime is 66986407. The reversal of 66986401 is 10468966.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10468966 = 2 ⋅5234483.

It can be written as a sum of positive squares in 2 ways, for example, as 57744801 + 9241600 = 7599^2 + 3040^2 .

It is a cyclic number.

It is not a de Polignac number, because 66986401 - 2⁹ = 66985889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66986407) 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, 50010 + ... + 51331.

It is an arithmetic number, because the mean of its divisors is an integer number (16772101).

Almost surely, 2^66986401 is an apocalyptic number.

It is an amenable number.

66986401 is a deficient number, since it is larger than the sum of its proper divisors (102003).

66986401 is a wasteful number, since it uses less digits than its factorization.

66986401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102002.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 66986401 is about 8184.5220385799. The cubic root of 66986401 is about 406.1273290844.

The spelling of 66986401 in words is "sixty-six million, nine hundred eighty-six thousand, four hundred one".