20561273 has 2 divisors, whose sum is σ = 20561274. Its totient is φ = 20561272.

The previous prime is 20561263. The next prime is 20561291. The reversal of 20561273 is 37216502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19333609 + 1227664 = 4397^2 + 1108^2 .

It is a cyclic number.

It is not a de Polignac number, because 20561273 - 2⁴ = 20561257 is a prime.

It is not a weakly prime, because it can be changed into another prime (20561263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10280636 + 10280637.

It is an arithmetic number, because the mean of its divisors is an integer number (10280637).

Almost surely, 2^20561273 is an apocalyptic number.

It is an amenable number.

20561273 is a deficient number, since it is larger than the sum of its proper divisors (1).

20561273 is an equidigital number, since it uses as much as digits as its factorization.

20561273 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 20561273 is about 4534.4539913864. The cubic root of 20561273 is about 273.9575875177.

Adding to 20561273 its reverse (37216502), we get a palindrome (57777775).

The spelling of 20561273 in words is "twenty million, five hundred sixty-one thousand, two hundred seventy-three".