64515163621 has 2 divisors, whose sum is σ = 64515163622. Its totient is φ = 64515163620.

The previous prime is 64515163619. The next prime is 64515163663. The reversal of 64515163621 is 12636151546.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61313188225 + 3201975396 = 247615^2 + 56586^2 .

It is a cyclic number.

It is not a de Polignac number, because 64515163621 - 2¹ = 64515163619 is a prime.

Together with 64515163619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64515163681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32257581810 + 32257581811.

It is an arithmetic number, because the mean of its divisors is an integer number (32257581811).

Almost surely, 2^64515163621 is an apocalyptic number.

It is an amenable number.

64515163621 is a deficient number, since it is larger than the sum of its proper divisors (1).

64515163621 is an equidigital number, since it uses as much as digits as its factorization.

64515163621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 40.

The spelling of 64515163621 in words is "sixty-four billion, five hundred fifteen million, one hundred sixty-three thousand, six hundred twenty-one".