20261161 has 4 divisors (see below), whose sum is σ = 21453012. Its totient is φ = 19069312.

The previous prime is 20261147. The next prime is 20261173. The reversal of 20261161 is 16116202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16116202 = 2 ⋅8058101.

It can be written as a sum of positive squares in 2 ways, for example, as 8667136 + 11594025 = 2944^2 + 3405^2 .

It is a cyclic number.

It is not a de Polignac number, because 20261161 - 2⁹ = 20260649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20261191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 595900 + ... + 595933.

It is an arithmetic number, because the mean of its divisors is an integer number (5363253).

Almost surely, 2^20261161 is an apocalyptic number.

It is an amenable number.

20261161 is a deficient number, since it is larger than the sum of its proper divisors (1191851).

20261161 is a wasteful number, since it uses less digits than its factorization.

20261161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1191850.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20261161 is about 4501.2399402831. The cubic root of 20261161 is about 272.6181559818.

Adding to 20261161 its reverse (16116202), we get a palindrome (36377363).

The spelling of 20261161 in words is "twenty million, two hundred sixty-one thousand, one hundred sixty-one".