641569839 has 4 divisors (see below), whose sum is σ = 855426456. Its totient is φ = 427713224.

The previous prime is 641569781. The next prime is 641569909. The reversal of 641569839 is 938965146.

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 641569839 - 2²⁰ = 640521263 is a prime.

It is a super-2 number, since 2×641569839² = 823223716628971842, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 641569791 and 641569800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641569739) 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, 106928304 + ... + 106928309.

It is an arithmetic number, because the mean of its divisors is an integer number (213856614).

Almost surely, 2^641569839 is an apocalyptic number.

641569839 is a deficient number, since it is larger than the sum of its proper divisors (213856617).

641569839 is a wasteful number, since it uses less digits than its factorization.

641569839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213856616.

The product of its digits is 1399680, while the sum is 51.

The square root of 641569839 is about 25329.2289460220. The cubic root of 641569839 is about 862.4779081088.

The spelling of 641569839 in words is "six hundred forty-one million, five hundred sixty-nine thousand, eight hundred thirty-nine".