66551657 has 2 divisors, whose sum is σ = 66551658. Its totient is φ = 66551656.

The previous prime is 66551647. The next prime is 66551669. The reversal of 66551657 is 75615566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34527376 + 32024281 = 5876^2 + 5659^2 .

It is a cyclic number.

It is not a de Polignac number, because 66551657 - 2⁶ = 66551593 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66551647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33275828 + 33275829.

It is an arithmetic number, because the mean of its divisors is an integer number (33275829).

Almost surely, 2^66551657 is an apocalyptic number.

It is an amenable number.

66551657 is a deficient number, since it is larger than the sum of its proper divisors (1).

66551657 is an equidigital number, since it uses as much as digits as its factorization.

66551657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 41.

The square root of 66551657 is about 8157.9198941887. The cubic root of 66551657 is about 405.2468281505.

The spelling of 66551657 in words is "sixty-six million, five hundred fifty-one thousand, six hundred fifty-seven".