181458064561 has 2 divisors, whose sum is σ = 181458064562. Its totient is φ = 181458064560.

The previous prime is 181458064559. The next prime is 181458064577. The reversal of 181458064561 is 165460854181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158200289536 + 23257775025 = 397744^2 + 152505^2 .

It is a cyclic number.

It is not a de Polignac number, because 181458064561 - 2¹ = 181458064559 is a prime.

Together with 181458064559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (181458064061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90729032280 + 90729032281.

It is an arithmetic number, because the mean of its divisors is an integer number (90729032281).

Almost surely, 2^181458064561 is an apocalyptic number.

It is an amenable number.

181458064561 is a deficient number, since it is larger than the sum of its proper divisors (1).

181458064561 is an equidigital number, since it uses as much as digits as its factorization.

181458064561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 921600, while the sum is 49.

The spelling of 181458064561 in words is "one hundred eighty-one billion, four hundred fifty-eight million, sixty-four thousand, five hundred sixty-one".