20781024 has 72 divisors (see below), whose sum is σ = 59993640. Its totient is φ = 6293760.

The previous prime is 20781017. The next prime is 20781031. The reversal of 20781024 is 42018702.

It is an interprime number because it is at equal distance from previous prime (20781017) and next prime (20781031).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 20780985 and 20781003.

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, 10722 + ... + 12510.

It is an arithmetic number, because the mean of its divisors is an integer number (833245).

Almost surely, 2^20781024 is an apocalyptic number.

20781024 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20781024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29996820).

20781024 is an abundant number, since it is smaller than the sum of its proper divisors (39212616).

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

20781024 is a wasteful number, since it uses less digits than its factorization.

20781024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1824 (or 1805 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 20781024 is about 4558.6208440712. The cubic root of 20781024 is about 274.9301155754.

Adding to 20781024 its reverse (42018702), we get a palindrome (62799726).

The spelling of 20781024 in words is "twenty million, seven hundred eighty-one thousand, twenty-four".