20786661 has 12 divisors (see below), whose sum is σ = 34314592. Its totient is φ = 11878056.

The previous prime is 20786651. The next prime is 20786669. The reversal of 20786661 is 16668702.

It is a happy number.

It is not a de Polignac number, because 20786661 - 2⁹ = 20786149 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 (20786669) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 164911 + ... + 165036.

Almost surely, 2^20786661 is an apocalyptic number.

20786661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20786661 is a deficient number, since it is larger than the sum of its proper divisors (13527931).

20786661 is a wasteful number, since it uses less digits than its factorization.

20786661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329960 (or 329957 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 20786661 is about 4559.2390812503. The cubic root of 20786661 is about 274.9549722420.

It can be divided in two parts, 207 and 86661, that added together give a palindrome (86868).

The spelling of 20786661 in words is "twenty million, seven hundred eighty-six thousand, six hundred sixty-one".