65123581381 has 2 divisors, whose sum is σ = 65123581382. Its totient is φ = 65123581380.

The previous prime is 65123581363. The next prime is 65123581409. The reversal of 65123581381 is 18318532156.

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., 62717188356 + 2406393025 = 250434^2 + 49055^2 .

It is a cyclic number.

It is not a de Polignac number, because 65123581381 - 2²⁵ = 65090026949 is a prime.

It is a super-2 number, since 2×65123581381² (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 (65123584381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32561790690 + 32561790691.

It is an arithmetic number, because the mean of its divisors is an integer number (32561790691).

Almost surely, 2^65123581381 is an apocalyptic number.

It is an amenable number.

65123581381 is a deficient number, since it is larger than the sum of its proper divisors (1).

65123581381 is an equidigital number, since it uses as much as digits as its factorization.

65123581381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 172800, while the sum is 43.

The spelling of 65123581381 in words is "sixty-five billion, one hundred twenty-three million, five hundred eighty-one thousand, three hundred eighty-one".