66684431 has 8 divisors (see below), whose sum is σ = 73349328. Its totient is φ = 60621000.

The previous prime is 66684377. The next prime is 66684461. The reversal of 66684431 is 13448666.

It is a de Polignac number, because none of the positive numbers 2^k-66684431 is a prime.

It is a super-2 number, since 2×66684431² = 8893626675587522, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66684461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23720 + ... + 26381.

It is an arithmetic number, because the mean of its divisors is an integer number (9168666).

Almost surely, 2^66684431 is an apocalyptic number.

66684431 is a deficient number, since it is larger than the sum of its proper divisors (6664897).

66684431 is an equidigital number, since it uses as much as digits as its factorization.

66684431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50134 (or 50112 counting only the distinct ones).

The product of its digits is 82944, while the sum is 38.

The square root of 66684431 is about 8166.0535756264. The cubic root of 66684431 is about 405.5161452610.

The spelling of 66684431 in words is "sixty-six million, six hundred eighty-four thousand, four hundred thirty-one".