666731641 has 16 divisors (see below), whose sum is σ = 723096000. Its totient is φ = 612698688.

The previous prime is 666731621. The next prime is 666731651. The reversal of 666731641 is 146137666.

It is a cyclic number.

It is not a de Polignac number, because 666731641 - 2¹¹ = 666729593 is a prime.

It is a super-2 number, since 2×666731641² = 889062162221105762, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666731594 and 666731603.

It is not an unprimeable number, because it can be changed into a prime (666731621) 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 15 ways as a sum of consecutive naturals, for example, 118995 + ... + 124471.

It is an arithmetic number, because the mean of its divisors is an integer number (45193500).

Almost surely, 2^666731641 is an apocalyptic number.

It is an amenable number.

666731641 is a deficient number, since it is larger than the sum of its proper divisors (56364359).

666731641 is a wasteful number, since it uses less digits than its factorization.

666731641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5688.

The product of its digits is 108864, while the sum is 40.

The square root of 666731641 is about 25821.1471666152. The cubic root of 666731641 is about 873.6088439685.

The spelling of 666731641 in words is "six hundred sixty-six million, seven hundred thirty-one thousand, six hundred forty-one".