20102840 has 96 divisors (see below), whose sum is σ = 50397120. Its totient is φ = 7206912.

The previous prime is 20102837. The next prime is 20102861. The reversal of 20102840 is 4820102.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 427697 + ... + 427743.

It is an arithmetic number, because the mean of its divisors is an integer number (524970).

Almost surely, 2^20102840 is an apocalyptic number.

20102840 is a gapful number since it is divisible by the number (20) 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 20102840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25198560).

20102840 is an abundant number, since it is smaller than the sum of its proper divisors (30294280).

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

20102840 is a wasteful number, since it uses less digits than its factorization.

20102840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 20102840 is about 4483.6190739179. The cubic root of 20102840 is about 271.9062176687.

Adding to 20102840 its reverse (4820102), we get a palindrome (24922942).

The spelling of 20102840 in words is "twenty million, one hundred two thousand, eight hundred forty".