20561284 has 24 divisors (see below), whose sum is σ = 36673560. Its totient is φ = 10085376.

The previous prime is 20561273. The next prime is 20561291. The reversal of 20561284 is 48216502.

It can be written as a sum of positive squares in 4 ways, for example, as 3504384 + 17056900 = 1872^2 + 4130^2 .

It is an unprimeable number.

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, 76302 + ... + 76570.

It is an arithmetic number, because the mean of its divisors is an integer number (1528065).

Almost surely, 2^20561284 is an apocalyptic number.

It is an amenable number.

20561284 is a deficient number, since it is larger than the sum of its proper divisors (16112276).

20561284 is a wasteful number, since it uses less digits than its factorization.

20561284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 567 (or 565 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 20561284 is about 4534.4552043217. The cubic root of 20561284 is about 273.9576363723.

Adding to 20561284 its reverse (48216502), we get a palindrome (68777786).

The spelling of 20561284 in words is "twenty million, five hundred sixty-one thousand, two hundred eighty-four".