641312616521 has 2 divisors, whose sum is σ = 641312616522. Its totient is φ = 641312616520.

The previous prime is 641312616463. The next prime is 641312616587. The reversal of 641312616521 is 125616213146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 476602452496 + 164710164025 = 690364^2 + 405845^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641312616521 is a prime.

It is a super-2 number, since 2×641312616521² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (641312616121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320656308260 + 320656308261.

It is an arithmetic number, because the mean of its divisors is an integer number (320656308261).

Almost surely, 2^641312616521 is an apocalyptic number.

It is an amenable number.

641312616521 is a deficient number, since it is larger than the sum of its proper divisors (1).

641312616521 is an equidigital number, since it uses as much as digits as its factorization.

641312616521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 38.

Adding to 641312616521 its reverse (125616213146), we get a palindrome (766928829667).

The spelling of 641312616521 in words is "six hundred forty-one billion, three hundred twelve million, six hundred sixteen thousand, five hundred twenty-one".