20831980 has 48 divisors (see below), whose sum is σ = 49603680. Its totient is φ = 7285248.

The previous prime is 20831959. The next prime is 20831981. The reversal of 20831980 is 8913802.

It is not an unprimeable number, because it can be changed into a prime (20831981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2832 + ... + 7048.

It is an arithmetic number, because the mean of its divisors is an integer number (1033410).

Almost surely, 2^20831980 is an apocalyptic number.

20831980 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 20831980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24801840).

20831980 is an abundant number, since it is smaller than the sum of its proper divisors (28771700).

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

20831980 is a wasteful number, since it uses less digits than its factorization.

20831980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4258 (or 4256 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 20831980 is about 4564.2063932298. The cubic root of 20831980 is about 275.1546458013.

The spelling of 20831980 in words is "twenty million, eight hundred thirty-one thousand, nine hundred eighty".