165643420 has 12 divisors (see below), whose sum is σ = 347851224. Its totient is φ = 66257360.

The previous prime is 165643409. The next prime is 165643441. The reversal of 165643420 is 24346561.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4141066 + ... + 4141105.

It is an arithmetic number, because the mean of its divisors is an integer number (28987602).

Almost surely, 2^165643420 is an apocalyptic number.

165643420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165643420 is an abundant number, since it is smaller than the sum of its proper divisors (182207804).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165643420 is a wasteful number, since it uses less digits than its factorization.

165643420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8282180 (or 8282178 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 165643420 is about 12870.2532997607. The cubic root of 165643420 is about 549.1926667523.

Adding to 165643420 its reverse (24346561), we get a palindrome (189989981).

The spelling of 165643420 in words is "one hundred sixty-five million, six hundred forty-three thousand, four hundred twenty".