66513217 has 16 divisors (see below), whose sum is σ = 71786880. Its totient is φ = 61471872.

The previous prime is 66513203. The next prime is 66513283. The reversal of 66513217 is 71231566.

It is a 4-Lehmer number, since φ(66513217) divides (66513217-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 66513217 - 2²³ = 58124609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66513287) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107493 + ... + 108109.

It is an arithmetic number, because the mean of its divisors is an integer number (4486680).

Almost surely, 2^66513217 is an apocalyptic number.

It is an amenable number.

66513217 is a deficient number, since it is larger than the sum of its proper divisors (5273663).

66513217 is a wasteful number, since it uses less digits than its factorization.

66513217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792.

The product of its digits is 7560, while the sum is 31.

The square root of 66513217 is about 8155.5635611526. The cubic root of 66513217 is about 405.1687900823.

The spelling of 66513217 in words is "sixty-six million, five hundred thirteen thousand, two hundred seventeen".