641988729 has 6 divisors (see below), whose sum is σ = 927317066. Its totient is φ = 427992480.

The previous prime is 641988727. The next prime is 641988757. The reversal of 641988729 is 927889146.

It can be written as a sum of positive squares in only one way, i.e., 489515625 + 152473104 = 22125^2 + 12348^2 .

It is not a de Polignac number, because 641988729 - 2¹ = 641988727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641988727) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35666032 + ... + 35666049.

Almost surely, 2^641988729 is an apocalyptic number.

It is an amenable number.

641988729 is a deficient number, since it is larger than the sum of its proper divisors (285328337).

641988729 is a wasteful number, since it uses less digits than its factorization.

641988729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71332087 (or 71332084 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The square root of 641988729 is about 25337.4965022198. The cubic root of 641988729 is about 862.6655752696.

It can be divided in two parts, 64198 and 8729, that added together give a palindrome (72927).

The spelling of 641988729 in words is "six hundred forty-one million, nine hundred eighty-eight thousand, seven hundred twenty-nine".