20561606 has 8 divisors (see below), whose sum is σ = 33214944. Its totient is φ = 9489960.

The previous prime is 20561599. The next prime is 20561621. The reversal of 20561606 is 60616502.

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

It is a Harshad number since it is a multiple of its sum of digits (26), and also a Moran number because the ratio is a prime number: 790831 = 20561606 / (2 + 0 + 5 + 6 + 1 + 6 + 0 + 6).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 395390 + ... + 395441.

It is an arithmetic number, because the mean of its divisors is an integer number (4151868).

Almost surely, 2^20561606 is an apocalyptic number.

20561606 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

20561606 is a deficient number, since it is larger than the sum of its proper divisors (12653338).

20561606 is a wasteful number, since it uses less digits than its factorization.

20561606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790846.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20561606 is about 4534.4907101019. The cubic root of 20561606 is about 273.9590664694.

The spelling of 20561606 in words is "twenty million, five hundred sixty-one thousand, six hundred six".