66525649 has 2 divisors, whose sum is σ = 66525650. Its totient is φ = 66525648.

The previous prime is 66525647. The next prime is 66525671. The reversal of 66525649 is 94652566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34433424 + 32092225 = 5868^2 + 5665^2 .

It is a cyclic number.

It is not a de Polignac number, because 66525649 - 2¹ = 66525647 is a prime.

Together with 66525647, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (66525647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33262824 + 33262825.

It is an arithmetic number, because the mean of its divisors is an integer number (33262825).

Almost surely, 2^66525649 is an apocalyptic number.

It is an amenable number.

66525649 is a deficient number, since it is larger than the sum of its proper divisors (1).

66525649 is an equidigital number, since it uses as much as digits as its factorization.

66525649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 388800, while the sum is 43.

The square root of 66525649 is about 8156.3257046295. The cubic root of 66525649 is about 405.1940319055.

The spelling of 66525649 in words is "sixty-six million, five hundred twenty-five thousand, six hundred forty-nine".