165221623 has 16 divisors (see below), whose sum is σ = 200344320. Its totient is φ = 133013376.

The previous prime is 165221603. The next prime is 165221669. The reversal of 165221623 is 326122561.

It is a cyclic number.

It is not a de Polignac number, because 165221623 - 2¹³ = 165213431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 165221591 and 165221600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165221603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72540 + ... + 74782.

It is an arithmetic number, because the mean of its divisors is an integer number (12521520).

Almost surely, 2^165221623 is an apocalyptic number.

165221623 is a deficient number, since it is larger than the sum of its proper divisors (35122697).

165221623 is a wasteful number, since it uses less digits than its factorization.

165221623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2886.

The product of its digits is 4320, while the sum is 28.

The square root of 165221623 is about 12853.8563474157. The cubic root of 165221623 is about 548.7261129108.

It can be divided in two parts, 16522 and 1623, that added together give a triangular number (18145 = T₁₉₀).

The spelling of 165221623 in words is "one hundred sixty-five million, two hundred twenty-one thousand, six hundred twenty-three".