165072421 has 2 divisors, whose sum is σ = 165072422. Its totient is φ = 165072420.

The previous prime is 165072377. The next prime is 165072433. The reversal of 165072421 is 124270561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90440100 + 74632321 = 9510^2 + 8639^2 .

It is a cyclic number.

It is not a de Polignac number, because 165072421 - 2⁹ = 165071909 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165072421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165072461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82536210 + 82536211.

It is an arithmetic number, because the mean of its divisors is an integer number (82536211).

Almost surely, 2^165072421 is an apocalyptic number.

It is an amenable number.

165072421 is a deficient number, since it is larger than the sum of its proper divisors (1).

165072421 is an equidigital number, since it uses as much as digits as its factorization.

165072421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 165072421 is about 12848.0512530111. The cubic root of 165072421 is about 548.5608889958.

The spelling of 165072421 in words is "one hundred sixty-five million, seventy-two thousand, four hundred twenty-one".