20260661 has 4 divisors (see below), whose sum is σ = 20302752. Its totient is φ = 20218572.

The previous prime is 20260649. The next prime is 20260663. The reversal of 20260661 is 16606202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16606202 = 2 ⋅8303101.

It is a cyclic number.

It is not a de Polignac number, because 20260661 - 2¹⁴ = 20244277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20260663) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 20315 + ... + 21288.

It is an arithmetic number, because the mean of its divisors is an integer number (5075688).

Almost surely, 2^20260661 is an apocalyptic number.

It is an amenable number.

20260661 is a deficient number, since it is larger than the sum of its proper divisors (42091).

20260661 is an equidigital number, since it uses as much as digits as its factorization.

20260661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42090.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 20260661 is about 4501.1843996886. The cubic root of 20260661 is about 272.6159134285.

Adding to 20260661 its reverse (16606202), we get a palindrome (36866863).

The spelling of 20260661 in words is "twenty million, two hundred sixty thousand, six hundred sixty-one".