20671040 has 56 divisors (see below), whose sum is σ = 53019960. Its totient is φ = 7630848.

The previous prime is 20671033. The next prime is 20671073. The reversal of 20671040 is 4017602.

It can be written as a sum of positive squares in 4 ways, for example, as 23104 + 20647936 = 152^2 + 4544^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1676 + ... + 6644.

It is an arithmetic number, because the mean of its divisors is an integer number (946785).

Almost surely, 2^20671040 is an apocalyptic number.

20671040 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 20671040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26509980).

20671040 is an abundant number, since it is smaller than the sum of its proper divisors (32348920).

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

20671040 is a wasteful number, since it uses less digits than its factorization.

20671040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4999 (or 4989 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20671040 is about 4546.5415427553. The cubic root of 20671040 is about 274.4442329394. Note that the first 3 decimals are identical.

Adding to 20671040 its reverse (4017602), we get a palindrome (24688642).

The spelling of 20671040 in words is "twenty million, six hundred seventy-one thousand, forty".