641558241 has 9 divisors (see below), whose sum is σ = 926805009. Its totient is φ = 427654836.

The previous prime is 641558233. The next prime is 641558243. The reversal of 641558241 is 142855146.

It is a happy number.

The square root of 641558241 is 25329.

It is a perfect power (a square), and thus also a powerful number.

641558241 is a `hidden beast` number, since 64 + 1 + 558 + 2 + 41 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 641558241 - 2³ = 641558233 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 641558196 and 641558205.

It is not an unprimeable number, because it can be changed into a prime (641558243) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 71766 + ... + 80208.

Almost surely, 2^641558241 is an apocalyptic number.

641558241 is the 25329-th square number.

641558241 is the 12665-th centered octagonal number.

It is an amenable number.

641558241 is a deficient number, since it is larger than the sum of its proper divisors (285246768).

641558241 is an frugal number, since it uses more digits than its factorization.

641558241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16892 (or 8446 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The cubic root of 641558241 is about 862.4727109198.

Multiplying 641558241 by its sum of digits (36), we get a square (23096096676 = 151974²).

The spelling of 641558241 in words is "six hundred forty-one million, five hundred fifty-eight thousand, two hundred forty-one".