66508501 has 2 divisors, whose sum is σ = 66508502. Its totient is φ = 66508500.

The previous prime is 66508489. The next prime is 66508553. The reversal of 66508501 is 10580566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48860100 + 17648401 = 6990^2 + 4201^2 .

It is a cyclic number.

It is not a de Polignac number, because 66508501 - 2⁷ = 66508373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66508201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33254250 + 33254251.

It is an arithmetic number, because the mean of its divisors is an integer number (33254251).

Almost surely, 2^66508501 is an apocalyptic number.

It is an amenable number.

66508501 is a deficient number, since it is larger than the sum of its proper divisors (1).

66508501 is an equidigital number, since it uses as much as digits as its factorization.

66508501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 66508501 is about 8155.2744282458. The cubic root of 66508501 is about 405.1592139345.

It can be divided in two parts, 6650 and 8501, that added together give a palindrome (15151).

The spelling of 66508501 in words is "sixty-six million, five hundred eight thousand, five hundred one".