66835409 has 2 divisors, whose sum is σ = 66835410. Its totient is φ = 66835408.

The previous prime is 66835403. The next prime is 66835427. The reversal of 66835409 is 90453866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47059600 + 19775809 = 6860^2 + 4447^2 .

It is a cyclic number.

It is not a de Polignac number, because 66835409 - 2¹² = 66831313 is a prime.

It is not a weakly prime, because it can be changed into another prime (66835403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33417704 + 33417705.

It is an arithmetic number, because the mean of its divisors is an integer number (33417705).

Almost surely, 2^66835409 is an apocalyptic number.

It is an amenable number.

66835409 is a deficient number, since it is larger than the sum of its proper divisors (1).

66835409 is an equidigital number, since it uses as much as digits as its factorization.

66835409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 41.

The square root of 66835409 is about 8175.2925941522. The cubic root of 66835409 is about 405.8219531215.

The spelling of 66835409 in words is "sixty-six million, eight hundred thirty-five thousand, four hundred nine".