Search a number
-
+
20165561 = 131551197
BaseRepresentation
bin100110011101…
…1001110111001
31101221111221122
41030323032321
520130244221
62000115025
7333255503
oct114731671
941844848
1020165561
1110423759
126905a75
1342408b0
14296cd73
151b84eab
hex133b3b9

20165561 has 4 divisors (see below), whose sum is σ = 21716772. Its totient is φ = 18614352.

The previous prime is 20165557. The next prime is 20165567. The reversal of 20165561 is 16556102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4515625 + 15649936 = 2125^2 + 3956^2 .

It is a cyclic number.

It is not a de Polignac number, because 20165561 - 22 = 20165557 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20165561.

It is not an unprimeable number, because it can be changed into a prime (20165567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 775586 + ... + 775611.

It is an arithmetic number, because the mean of its divisors is an integer number (5429193).

Almost surely, 220165561 is an apocalyptic number.

It is an amenable number.

20165561 is a deficient number, since it is larger than the sum of its proper divisors (1551211).

20165561 is a wasteful number, since it uses less digits than its factorization.

20165561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1551210.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 20165561 is about 4490.6080879988. The cubic root of 20165561 is about 272.1887071763.

The spelling of 20165561 in words is "twenty million, one hundred sixty-five thousand, five hundred sixty-one".

Divisors: 1 13 1551197 20165561