21201040 has 120 divisors (see below), whose sum is σ = 60299712. Its totient is φ = 6789120.

The previous prime is 21201031. The next prime is 21201041. The reversal of 21201040 is 4010212.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21201041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 161775 + ... + 161905.

Almost surely, 2^21201040 is an apocalyptic number.

21201040 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 21201040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30149856).

21201040 is an abundant number, since it is smaller than the sum of its proper divisors (39098672).

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

21201040 is a wasteful number, since it uses less digits than its factorization.

21201040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21201040 is about 4604.4587086866. The cubic root of 21201040 is about 276.7700263801.

Adding to 21201040 its reverse (4010212), we get a palindrome (25211252).

It can be divided in two parts, 2120 and 1040, that added together give a triangular number (3160 = T₇₉).

The spelling of 21201040 in words is "twenty-one million, two hundred one thousand, forty".