20686340 has 12 divisors (see below), whose sum is σ = 43441356. Its totient is φ = 8274528.

The previous prime is 20686333. The next prime is 20686343. The reversal of 20686340 is 4368602.

It can be written as a sum of positive squares in 2 ways, for example, as 2979076 + 17707264 = 1726^2 + 4208^2 .

It is not an unprimeable number, because it can be changed into a prime (20686343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 517139 + ... + 517178.

It is an arithmetic number, because the mean of its divisors is an integer number (3620113).

Almost surely, 2^20686340 is an apocalyptic number.

20686340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20686340 is an abundant number, since it is smaller than the sum of its proper divisors (22755016).

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

20686340 is a wasteful number, since it uses less digits than its factorization.

20686340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034326 (or 1034324 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 20686340 is about 4548.2238291447. The cubic root of 20686340 is about 274.5119276660.

The spelling of 20686340 in words is "twenty million, six hundred eighty-six thousand, three hundred forty".