66415501 has 2 divisors, whose sum is σ = 66415502. Its totient is φ = 66415500.

The previous prime is 66415487. The next prime is 66415511. The reversal of 66415501 is 10551466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 35390601 + 31024900 = 5949^2 + 5570^2 .

It is a cyclic number.

It is not a de Polignac number, because 66415501 - 2⁷ = 66415373 is a prime.

It is a super-2 number, since 2×66415501² = 8822037546162002, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66415501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66415511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33207750 + 33207751.

It is an arithmetic number, because the mean of its divisors is an integer number (33207751).

Almost surely, 2^66415501 is an apocalyptic number.

It is an amenable number.

66415501 is a deficient number, since it is larger than the sum of its proper divisors (1).

66415501 is an equidigital number, since it uses as much as digits as its factorization.

66415501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 66415501 is about 8149.5706021851. The cubic root of 66415501 is about 404.9702787720.

Adding to 66415501 its reverse (10551466), we get a palindrome (76966967).

The spelling of 66415501 in words is "sixty-six million, four hundred fifteen thousand, five hundred one".