20391768 has 48 divisors (see below), whose sum is σ = 56019600. Its totient is φ = 6699840.

The previous prime is 20391737. The next prime is 20391781. The reversal of 20391768 is 86719302.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 11 ways as a sum of consecutive naturals, for example, 3118 + ... + 7106.

It is an arithmetic number, because the mean of its divisors is an integer number (1167075).

Almost surely, 2^20391768 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 20391768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28009800).

20391768 is an abundant number, since it is smaller than the sum of its proper divisors (35627832).

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

20391768 is a wasteful number, since it uses less digits than its factorization.

20391768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4072 (or 4065 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 20391768 is about 4515.7245265849. The cubic root of 20391768 is about 273.2026832809.

It can be divided in two parts, 2039176 and 8, that added together give a square (2039184 = 1428²).

The spelling of 20391768 in words is "twenty million, three hundred ninety-one thousand, seven hundred sixty-eight".