66038561 has 2 divisors, whose sum is σ = 66038562. Its totient is φ = 66038560.

The previous prime is 66038519. The next prime is 66038563. The reversal of 66038561 is 16583066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56851600 + 9186961 = 7540^2 + 3031^2 .

It is a cyclic number.

It is not a de Polignac number, because 66038561 - 2²² = 61844257 is a prime.

It is a super-2 number, since 2×66038561² = 8722183077901442, which contains 22 as substring.

Together with 66038563, 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 (66038563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33019280 + 33019281.

It is an arithmetic number, because the mean of its divisors is an integer number (33019281).

Almost surely, 2^66038561 is an apocalyptic number.

It is an amenable number.

66038561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66038561 is an equidigital number, since it uses as much as digits as its factorization.

66038561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 66038561 is about 8126.4113235794. The cubic root of 66038561 is about 404.2026909093.

The spelling of 66038561 in words is "sixty-six million, thirty-eight thousand, five hundred sixty-one".