20983440 has 160 divisors (see below), whose sum is σ = 71245440. Its totient is φ = 5087232.

The previous prime is 20983439. The next prime is 20983453. The reversal of 20983440 is 4438902.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20983398 and 20983407.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 150891 + ... + 151029.

It is an arithmetic number, because the mean of its divisors is an integer number (445284).

Almost surely, 2^20983440 is an apocalyptic number.

20983440 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 20983440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35622720).

20983440 is an abundant number, since it is smaller than the sum of its proper divisors (50262000).

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

20983440 is a wasteful number, since it uses less digits than its factorization.

20983440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 20983440 is about 4580.7684944778. The cubic root of 20983440 is about 275.8198782746.

The spelling of 20983440 in words is "twenty million, nine hundred eighty-three thousand, four hundred forty".