165541621406939 has 2 divisors, whose sum is σ = 165541621406940. Its totient is φ = 165541621406938.

The previous prime is 165541621406929. The next prime is 165541621406971. The reversal of 165541621406939 is 939604126145561.

It is a happy number.

165541621406939 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 is a cyclic number.

It is not a de Polignac number, because 165541621406939 - 2²⁰ = 165541620358363 is a prime.

It is not a weakly prime, because it can be changed into another prime (165541621406929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82770810703469 + 82770810703470.

It is an arithmetic number, because the mean of its divisors is an integer number (82770810703470).

Almost surely, 2^{165541621406939} is an apocalyptic number.

165541621406939 is a deficient number, since it is larger than the sum of its proper divisors (1).

165541621406939 is an equidigital number, since it uses as much as digits as its factorization.

165541621406939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41990400, while the sum is 62.

The spelling of 165541621406939 in words is "one hundred sixty-five trillion, five hundred forty-one billion, six hundred twenty-one million, four hundred six thousand, nine hundred thirty-nine".