66809412 has 18 divisors (see below), whose sum is σ = 168879438. Its totient is φ = 22269792.

The previous prime is 66809399. The next prime is 66809443. The reversal of 66809412 is 21490866.

66809412 is digitally balanced in base 9, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 60933636 + 5875776 = 7806^2 + 2424^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 1855817 = 66809412 / (6 + 6 + 8 + 0 + 9 + 4 + 1 + 2).

66809412 is strictly pandigital in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 927873 + ... + 927944.

It is an arithmetic number, because the mean of its divisors is an integer number (9382191).

Almost surely, 2^66809412 is an apocalyptic number.

It is an amenable number.

66809412 is an abundant number, since it is smaller than the sum of its proper divisors (102070026).

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

66809412 is a wasteful number, since it uses less digits than its factorization.

66809412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1855827 (or 1855822 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 66809412 is about 8173.7024658352. The cubic root of 66809412 is about 405.7693287134.

The spelling of 66809412 in words is "sixty-six million, eight hundred nine thousand, four hundred twelve".