66765531 has 32 divisors (see below), whose sum is σ = 104509440. Its totient is φ = 37125504.

The previous prime is 66765493. The next prime is 66765533. The reversal of 66765531 is 13556766.

It is not a de Polignac number, because 66765531 - 2¹⁵ = 66732763 is a prime.

It is a super-2 number, since 2×66765531² = 8915272259423922, 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 66765531.

It is not an unprimeable number, because it can be changed into a prime (66765533) 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 31 ways as a sum of consecutive naturals, for example, 248065 + ... + 248333.

It is an arithmetic number, because the mean of its divisors is an integer number (3265920).

Almost surely, 2^66765531 is an apocalyptic number.

66765531 is a deficient number, since it is larger than the sum of its proper divisors (37743909).

66765531 is a wasteful number, since it uses less digits than its factorization.

66765531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555.

The product of its digits is 113400, while the sum is 39.

The square root of 66765531 is about 8171.0177456667. The cubic root of 66765531 is about 405.6804716543.

The spelling of 66765531 in words is "sixty-six million, seven hundred sixty-five thousand, five hundred thirty-one".