66025409 has 2 divisors, whose sum is σ = 66025410. Its totient is φ = 66025408.

The previous prime is 66025397. The next prime is 66025411. The reversal of 66025409 is 90452066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42211009 + 23814400 = 6497^2 + 4880^2 .

It is a cyclic number.

It is not a de Polignac number, because 66025409 - 2⁸ = 66025153 is a prime.

Together with 66025411, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66025429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33012704 + 33012705.

It is an arithmetic number, because the mean of its divisors is an integer number (33012705).

Almost surely, 2^66025409 is an apocalyptic number.

It is an amenable number.

66025409 is a deficient number, since it is larger than the sum of its proper divisors (1).

66025409 is an equidigital number, since it uses as much as digits as its factorization.

66025409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 66025409 is about 8125.6020700007. The cubic root of 66025409 is about 404.1758559477.

The spelling of 66025409 in words is "sixty-six million, twenty-five thousand, four hundred nine".