6364511981 has 2 divisors, whose sum is σ = 6364511982. Its totient is φ = 6364511980.

The previous prime is 6364511963. The next prime is 6364512013. The reversal of 6364511981 is 1891154636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5938089481 + 426422500 = 77059^2 + 20650^2 .

It is a cyclic number.

It is not a de Polignac number, because 6364511981 - 2⁶ = 6364511917 is a prime.

It is a super-2 number, since 2×6364511981² = 81014025512585088722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6364511911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3182255990 + 3182255991.

It is an arithmetic number, because the mean of its divisors is an integer number (3182255991).

Almost surely, 2^6364511981 is an apocalyptic number.

It is an amenable number.

6364511981 is a deficient number, since it is larger than the sum of its proper divisors (1).

6364511981 is an equidigital number, since it uses as much as digits as its factorization.

6364511981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 44.

The square root of 6364511981 is about 79777.8915552423. The cubic root of 6364511981 is about 1853.1974877535.

The spelling of 6364511981 in words is "six billion, three hundred sixty-four million, five hundred eleven thousand, nine hundred eighty-one".