641561445 has 32 divisors (see below), whose sum is σ = 1303491840. Its totient is φ = 293284800.

The previous prime is 641561443. The next prime is 641561447. The reversal of 641561445 is 544165146.

641561445 is a `hidden beast` number, since 64 + 156 + 1 + 445 = 666.

It is an interprime number because it is at equal distance from previous prime (641561443) and next prime (641561447).

It is not a de Polignac number, because 641561445 - 2¹ = 641561443 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641561441) 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 31 ways as a sum of consecutive naturals, for example, 338506 + ... + 340395.

It is an arithmetic number, because the mean of its divisors is an integer number (40734120).

Almost surely, 2^641561445 is an apocalyptic number.

It is an amenable number.

641561445 is an abundant number, since it is smaller than the sum of its proper divisors (661930395).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

641561445 is a wasteful number, since it uses less digits than its factorization.

641561445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678922 (or 678916 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The square root of 641561445 is about 25329.0632475818. The cubic root of 641561445 is about 862.4741466731.

The spelling of 641561445 in words is "six hundred forty-one million, five hundred sixty-one thousand, four hundred forty-five".