20541561 has 8 divisors (see below), whose sum is σ = 28272384. Its totient is φ = 13252560.

The previous prime is 20541557. The next prime is 20541571. The reversal of 20541561 is 16514502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20541561 - 2² = 20541557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20541511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110346 + ... + 110531.

It is an arithmetic number, because the mean of its divisors is an integer number (3534048).

Almost surely, 2^20541561 is an apocalyptic number.

It is an amenable number.

20541561 is a deficient number, since it is larger than the sum of its proper divisors (7730823).

20541561 is a wasteful number, since it uses less digits than its factorization.

20541561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220911.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 20541561 is about 4532.2798898568. The cubic root of 20541561 is about 273.8700122232.

The spelling of 20541561 in words is "twenty million, five hundred forty-one thousand, five hundred sixty-one".