64539001781 has 2 divisors, whose sum is σ = 64539001782. Its totient is φ = 64539001780.

The previous prime is 64539001771. The next prime is 64539001799. The reversal of 64539001781 is 18710093546.

64539001781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51057469681 + 13481532100 = 225959^2 + 116110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64539001781 is a prime.

It is a super-2 number, since 2×64539001781² (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 (64539001721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32269500890 + 32269500891.

It is an arithmetic number, because the mean of its divisors is an integer number (32269500891).

Almost surely, 2^64539001781 is an apocalyptic number.

It is an amenable number.

64539001781 is a deficient number, since it is larger than the sum of its proper divisors (1).

64539001781 is an equidigital number, since it uses as much as digits as its factorization.

64539001781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 44.

The spelling of 64539001781 in words is "sixty-four billion, five hundred thirty-nine million, one thousand, seven hundred eighty-one".