20561277 has 32 divisors (see below), whose sum is σ = 31334400. Its totient is φ = 11880000.

The previous prime is 20561273. The next prime is 20561291. The reversal of 20561277 is 77216502.

It is not a de Polignac number, because 20561277 - 2² = 20561273 is a prime.

It is a super-3 number, since 3×20561277³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 103224 + ... + 103422.

It is an arithmetic number, because the mean of its divisors is an integer number (979200).

Almost surely, 2^20561277 is an apocalyptic number.

It is an amenable number.

20561277 is a deficient number, since it is larger than the sum of its proper divisors (10773123).

20561277 is a wasteful number, since it uses less digits than its factorization.

20561277 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345.

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 20561277 is about 4534.4544324538. The cubic root of 20561277 is about 273.9576052830.

Adding to 20561277 its reverse (77216502), we get a palindrome (97777779).

It can be divided in two parts, 2056 and 1277, that added together give a palindrome (3333).

The spelling of 20561277 in words is "twenty million, five hundred sixty-one thousand, two hundred seventy-seven".