20867640 has 32 divisors (see below), whose sum is σ = 62603280. Its totient is φ = 5564672.

The previous prime is 20867603. The next prime is 20867663. The reversal of 20867640 is 4676802.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 86829 + ... + 87068.

Almost surely, 2^20867640 is an apocalyptic number.

20867640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20867640 is an abundant number, since it is smaller than the sum of its proper divisors (41735640).

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

20867640 is a wasteful number, since it uses less digits than its factorization.

20867640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173911 (or 173907 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 20867640 is about 4568.1112070526. Note that the first 3 decimals coincide. The cubic root of 20867640 is about 275.3115587348.

The spelling of 20867640 in words is "twenty million, eight hundred sixty-seven thousand, six hundred forty".