165547239421 has 2 divisors, whose sum is σ = 165547239422. Its totient is φ = 165547239420.

The previous prime is 165547239329. The next prime is 165547239433. The reversal of 165547239421 is 124932745561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129146796900 + 36400442521 = 359370^2 + 190789^2 .

It is a cyclic number.

It is not a de Polignac number, because 165547239421 - 2¹³ = 165547231229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165547239491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82773619710 + 82773619711.

It is an arithmetic number, because the mean of its divisors is an integer number (82773619711).

Almost surely, 2^165547239421 is an apocalyptic number.

It is an amenable number.

165547239421 is a deficient number, since it is larger than the sum of its proper divisors (1).

165547239421 is an equidigital number, since it uses as much as digits as its factorization.

165547239421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1814400, while the sum is 49.

The spelling of 165547239421 in words is "one hundred sixty-five billion, five hundred forty-seven million, two hundred thirty-nine thousand, four hundred twenty-one".