641971549 has 2 divisors, whose sum is σ = 641971550. Its totient is φ = 641971548.

The previous prime is 641971537. The next prime is 641971559. The reversal of 641971549 is 945179146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 618516900 + 23454649 = 24870^2 + 4843^2 .

It is a cyclic number.

It is not a de Polignac number, because 641971549 - 2²⁷ = 507753821 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 641971499 and 641971508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641971559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320985774 + 320985775.

It is an arithmetic number, because the mean of its divisors is an integer number (320985775).

Almost surely, 2^641971549 is an apocalyptic number.

It is an amenable number.

641971549 is a deficient number, since it is larger than the sum of its proper divisors (1).

641971549 is an equidigital number, since it uses as much as digits as its factorization.

641971549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 272160, while the sum is 46.

The square root of 641971549 is about 25337.1574767179. The cubic root of 641971549 is about 862.6578800531.

The spelling of 641971549 in words is "six hundred forty-one million, nine hundred seventy-one thousand, five hundred forty-nine".