165743277421 has 2 divisors, whose sum is σ = 165743277422. Its totient is φ = 165743277420.

The previous prime is 165743277377. The next prime is 165743277433. The reversal of 165743277421 is 124772347561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165319494025 + 423783396 = 406595^2 + 20586^2 .

It is a cyclic number.

It is not a de Polignac number, because 165743277421 - 2³¹ = 163595793773 is a prime.

It is a super-2 number, since 2×165743277421² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165743277461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82871638710 + 82871638711.

It is an arithmetic number, because the mean of its divisors is an integer number (82871638711).

Almost surely, 2^165743277421 is an apocalyptic number.

It is an amenable number.

165743277421 is a deficient number, since it is larger than the sum of its proper divisors (1).

165743277421 is an equidigital number, since it uses as much as digits as its factorization.

165743277421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1975680, while the sum is 49.

The spelling of 165743277421 in words is "one hundred sixty-five billion, seven hundred forty-three million, two hundred seventy-seven thousand, four hundred twenty-one".