641166639 has 4 divisors (see below), whose sum is σ = 854888856. Its totient is φ = 427444424.

The previous prime is 641166613. The next prime is 641166661. The reversal of 641166639 is 936661146.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 641166639 - 2¹³ = 641158447 is a prime.

It is a super-2 number, since 2×641166639² = 822189317933112642, 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 641166639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641165639) 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, 106861104 + ... + 106861109.

It is an arithmetic number, because the mean of its divisors is an integer number (213722214).

Almost surely, 2^641166639 is an apocalyptic number.

641166639 is a deficient number, since it is larger than the sum of its proper divisors (213722217).

641166639 is a wasteful number, since it uses less digits than its factorization.

641166639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213722216.

The product of its digits is 139968, while the sum is 42.

The square root of 641166639 is about 25321.2685108784. The cubic root of 641166639 is about 862.2971930638.

The spelling of 641166639 in words is "six hundred forty-one million, one hundred sixty-six thousand, six hundred thirty-nine".