20561278 has 8 divisors (see below), whose sum is σ = 31498272. Its totient is φ = 10061856.

The previous prime is 20561273. The next prime is 20561291. The reversal of 20561278 is 87216502.

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

It is a super-3 number, since 3×20561278³ (a number of 23 digits) contains 333 as substring.

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 3 ways as a sum of consecutive naturals, for example, 109275 + ... + 109462.

It is an arithmetic number, because the mean of its divisors is an integer number (3937284).

Almost surely, 2^20561278 is an apocalyptic number.

20561278 is a deficient number, since it is larger than the sum of its proper divisors (10936994).

20561278 is a wasteful number, since it uses less digits than its factorization.

20561278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218786.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 20561278 is about 4534.4545427207. The cubic root of 20561278 is about 273.9576097243.

The spelling of 20561278 in words is "twenty million, five hundred sixty-one thousand, two hundred seventy-eight".