21313040 has 60 divisors (see below), whose sum is σ = 57653676. Its totient is φ = 7305984.

The previous prime is 21313037. The next prime is 21313063. The reversal of 21313040 is 4031312.

It can be written as a sum of positive squares in 2 ways, for example, as 9834496 + 11478544 = 3136^2 + 3388^2 .

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1202 + ... + 6638.

Almost surely, 2^21313040 is an apocalyptic number.

21313040 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 21313040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28826838).

21313040 is an abundant number, since it is smaller than the sum of its proper divisors (36340636).

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

21313040 is a wasteful number, since it uses less digits than its factorization.

21313040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5464 (or 5451 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21313040 is about 4616.6048130634. The cubic root of 21313040 is about 277.2565405192.

Adding to 21313040 its reverse (4031312), we get a palindrome (25344352).

The spelling of 21313040 in words is "twenty-one million, three hundred thirteen thousand, forty".