21203040 has 96 divisors (see below), whose sum is σ = 67447296. Its totient is φ = 5598720.

The previous prime is 21203023. The next prime is 21203041. The reversal of 21203040 is 4030212.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78105 + ... + 78375.

It is an arithmetic number, because the mean of its divisors is an integer number (702576).

Almost surely, 2^21203040 is an apocalyptic number.

21203040 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 21203040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33723648).

21203040 is an abundant number, since it is smaller than the sum of its proper divisors (46244256).

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

21203040 is a wasteful number, since it uses less digits than its factorization.

21203040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452 (or 444 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21203040 is about 4604.6758843593. The cubic root of 21203040 is about 276.7787291394.

Adding to 21203040 its reverse (4030212), we get a palindrome (25233252).

The spelling of 21203040 in words is "twenty-one million, two hundred three thousand, forty".