165120425405021 has 2 divisors, whose sum is σ = 165120425405022. Its totient is φ = 165120425405020.

The previous prime is 165120425405011. The next prime is 165120425405041. The reversal of 165120425405021 is 120504524021561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138789015765625 + 26331409639396 = 11780875^2 + 5131414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165120425405021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165120425405011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82560212702510 + 82560212702511.

It is an arithmetic number, because the mean of its divisors is an integer number (82560212702511).

Almost surely, 2^{165120425405021} is an apocalyptic number.

It is an amenable number.

165120425405021 is a deficient number, since it is larger than the sum of its proper divisors (1).

165120425405021 is an equidigital number, since it uses as much as digits as its factorization.

165120425405021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96000, while the sum is 38.

Adding to 165120425405021 its reverse (120504524021561), we get a palindrome (285624949426582).

The spelling of 165120425405021 in words is "one hundred sixty-five trillion, one hundred twenty billion, four hundred twenty-five million, four hundred five thousand, twenty-one".