21143040 has 80 divisors (see below), whose sum is σ = 67616208. Its totient is φ = 5636096.

The previous prime is 21143039. The next prime is 21143051. The reversal of 21143040 is 4034112.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6304 + ... + 9056.

Almost surely, 2^21143040 is an apocalyptic number.

21143040 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 21143040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33808104).

21143040 is an abundant number, since it is smaller than the sum of its proper divisors (46473168).

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

21143040 is an equidigital number, since it uses as much as digits as its factorization.

21143040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2779 (or 2763 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21143040 is about 4598.1561521984. The cubic root of 21143040 is about 276.5174079186.

Adding to 21143040 its reverse (4034112), we get a palindrome (25177152).

The spelling of 21143040 in words is "twenty-one million, one hundred forty-three thousand, forty".