20561650 has 12 divisors (see below), whose sum is σ = 38244762. Its totient is φ = 8224640.

The previous prime is 20561647. The next prime is 20561663. The reversal of 20561650 is 5616502.

It can be written as a sum of positive squares in 3 ways, for example, as 17715681 + 2845969 = 4209^2 + 1687^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 205567 + ... + 205666.

Almost surely, 2^20561650 is an apocalyptic number.

20561650 is a deficient number, since it is larger than the sum of its proper divisors (17683112).

20561650 is a wasteful number, since it uses less digits than its factorization.

20561650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411245 (or 411240 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 20561650 is about 4534.4955618018. The cubic root of 20561650 is about 273.9592618852.

The spelling of 20561650 in words is "twenty million, five hundred sixty-one thousand, six hundred fifty".