18861290947547 has 2 divisors, whose sum is σ = 18861290947548. Its totient is φ = 18861290947546.

The previous prime is 18861290947489. The next prime is 18861290947589. The reversal of 18861290947547 is 74574909216881.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18861290947547 - 2⁶ = 18861290947483 is a prime.

It is not a weakly prime, because it can be changed into another prime (18861290947747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9430645473773 + 9430645473774.

It is an arithmetic number, because the mean of its divisors is an integer number (9430645473774).

Almost surely, 2^{18861290947547} is an apocalyptic number.

18861290947547 is a deficient number, since it is larger than the sum of its proper divisors (1).

18861290947547 is an equidigital number, since it uses as much as digits as its factorization.

18861290947547 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 243855360, while the sum is 71.

The spelling of 18861290947547 in words is "eighteen trillion, eight hundred sixty-one billion, two hundred ninety million, nine hundred forty-seven thousand, five hundred forty-seven".