66812513 has 4 divisors (see below), whose sum is σ = 66829488. Its totient is φ = 66795540.

The previous prime is 66812509. The next prime is 66812573. The reversal of 66812513 is 31521866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66812513 - 2² = 66812509 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66812513.

It is not an unprimeable number, because it can be changed into a prime (66812573) 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 in 3 ways as a sum of consecutive naturals, for example, 818 + ... + 11588.

It is an arithmetic number, because the mean of its divisors is an integer number (16707372).

Almost surely, 2^66812513 is an apocalyptic number.

It is an amenable number.

66812513 is a deficient number, since it is larger than the sum of its proper divisors (16975).

66812513 is a wasteful number, since it uses less digits than its factorization.

66812513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16974.

The product of its digits is 8640, while the sum is 32.

The square root of 66812513 is about 8173.8921573507. The cubic root of 66812513 is about 405.7756066274.

The spelling of 66812513 in words is "sixty-six million, eight hundred twelve thousand, five hundred thirteen".