64102181981 has 2 divisors, whose sum is σ = 64102181982. Its totient is φ = 64102181980.

The previous prime is 64102181971. The next prime is 64102182077. The reversal of 64102181981 is 18918120146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61906416100 + 2195765881 = 248810^2 + 46859^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64102181981 is a prime.

It is a super-2 number, since 2×64102181981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64102181971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32051090990 + 32051090991.

It is an arithmetic number, because the mean of its divisors is an integer number (32051090991).

Almost surely, 2^64102181981 is an apocalyptic number.

It is an amenable number.

64102181981 is a deficient number, since it is larger than the sum of its proper divisors (1).

64102181981 is an equidigital number, since it uses as much as digits as its factorization.

64102181981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 41.

The spelling of 64102181981 in words is "sixty-four billion, one hundred two million, one hundred eighty-one thousand, nine hundred eighty-one".