20820688 has 30 divisors (see below), whose sum is σ = 46927986. Its totient is φ = 8922816.

The previous prime is 20820649. The next prime is 20820689. The reversal of 20820688 is 88602802.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17405584 + 3415104 = 4172^2 + 1848^2 .

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20820689) 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 5 ways as a sum of consecutive naturals, for example, 12495 + ... + 14062.

Almost surely, 2^20820688 is an apocalyptic number.

20820688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20820688 is an abundant number, since it is smaller than the sum of its proper divisors (26107298).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20820688 is a wasteful number, since it uses less digits than its factorization.

20820688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26579 (or 26566 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 34.

The square root of 20820688 is about 4562.9692087499. The cubic root of 20820688 is about 275.1049208460.

The spelling of 20820688 in words is "twenty million, eight hundred twenty thousand, six hundred eighty-eight".