21130040 has 32 divisors (see below), whose sum is σ = 48444480. Its totient is φ = 8291712.

The previous prime is 21130037. The next prime is 21130049. The reversal of 21130040 is 4003112.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130049) by changing a digit.

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, 2864 + ... + 7103.

It is an arithmetic number, because the mean of its divisors is an integer number (1513890).

Almost surely, 2^21130040 is an apocalyptic number.

21130040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21130040 is an abundant number, since it is smaller than the sum of its proper divisors (27314440).

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

21130040 is a wasteful number, since it uses less digits than its factorization.

21130040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10031 (or 10027 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21130040 is about 4596.7423247339. The cubic root of 21130040 is about 276.4607231765.

Adding to 21130040 its reverse (4003112), we get a palindrome (25133152).

The spelling of 21130040 in words is "twenty-one million, one hundred thirty thousand, forty".