20787312 has 80 divisors (see below), whose sum is σ = 66106880. Its totient is φ = 5481216.

The previous prime is 20787259. The next prime is 20787313. The reversal of 20787312 is 21378702.

It is a super-2 number, since 2×20787312² = 864224680370688, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20787312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20787313) 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 15 ways as a sum of consecutive naturals, for example, 1989 + ... + 6747.

It is an arithmetic number, because the mean of its divisors is an integer number (826336).

Almost surely, 2^20787312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20787312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33053440).

20787312 is an abundant number, since it is smaller than the sum of its proper divisors (45319568).

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

20787312 is a wasteful number, since it uses less digits than its factorization.

20787312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4790 (or 4784 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 20787312 is about 4559.3104741836. The cubic root of 20787312 is about 274.9578425734.

The spelling of 20787312 in words is "twenty million, seven hundred eighty-seven thousand, three hundred twelve".