641513281 has 2 divisors, whose sum is σ = 641513282. Its totient is φ = 641513280.

The previous prime is 641513251. The next prime is 641513291. The reversal of 641513281 is 182315146.

641513281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 641102400 + 410881 = 25320^2 + 641^2 .

It is a cyclic number.

It is not a de Polignac number, because 641513281 - 2⁷ = 641513153 is a prime.

It is a super-2 number, since 2×641513281² = 823078579398769922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (641513221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320756640 + 320756641.

It is an arithmetic number, because the mean of its divisors is an integer number (320756641).

Almost surely, 2^641513281 is an apocalyptic number.

It is an amenable number.

641513281 is a deficient number, since it is larger than the sum of its proper divisors (1).

641513281 is an equidigital number, since it uses as much as digits as its factorization.

641513281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 31.

The square root of 641513281 is about 25328.1124642165. The cubic root of 641513281 is about 862.4525632666.

The spelling of 641513281 in words is "six hundred forty-one million, five hundred thirteen thousand, two hundred eighty-one".