64146721321 has 2 divisors, whose sum is σ = 64146721322. Its totient is φ = 64146721320.

The previous prime is 64146721297. The next prime is 64146721337. The reversal of 64146721321 is 12312764146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56959072921 + 7187648400 = 238661^2 + 84780^2 .

It is a cyclic number.

It is not a de Polignac number, because 64146721321 - 2⁷ = 64146721193 is a prime.

It is a super-4 number, since 4×64146721321⁴ (a number of 44 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (64146721621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32073360660 + 32073360661.

It is an arithmetic number, because the mean of its divisors is an integer number (32073360661).

Almost surely, 2^64146721321 is an apocalyptic number.

It is an amenable number.

64146721321 is a deficient number, since it is larger than the sum of its proper divisors (1).

64146721321 is an equidigital number, since it uses as much as digits as its factorization.

64146721321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 37.

The spelling of 64146721321 in words is "sixty-four billion, one hundred forty-six million, seven hundred twenty-one thousand, three hundred twenty-one".