66531913 has 4 divisors (see below), whose sum is σ = 76036480. Its totient is φ = 57027348.

The previous prime is 66531911. The next prime is 66531917. The reversal of 66531913 is 31913566.

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 not a de Polignac number, because 66531913 - 2¹ = 66531911 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66531911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4752273 + ... + 4752286.

It is an arithmetic number, because the mean of its divisors is an integer number (19009120).

Almost surely, 2^66531913 is an apocalyptic number.

It is an amenable number.

66531913 is a deficient number, since it is larger than the sum of its proper divisors (9504567).

66531913 is an equidigital number, since it uses as much as digits as its factorization.

66531913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9504566.

The product of its digits is 14580, while the sum is 34.

The square root of 66531913 is about 8156.7096920266. The cubic root of 66531913 is about 405.2067490845.

The spelling of 66531913 in words is "sixty-six million, five hundred thirty-one thousand, nine hundred thirteen".