21043413 has 24 divisors (see below), whose sum is σ = 31918848. Its totient is φ = 13334112.

The previous prime is 21043409. The next prime is 21043423. The reversal of 21043413 is 31434012.

21043413 is a `hidden beast` number, since 210 + 43 + 413 = 666.

It is not a de Polignac number, because 21043413 - 2² = 21043409 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 57156 + ... + 57522.

It is an arithmetic number, because the mean of its divisors is an integer number (1329952).

Almost surely, 2^21043413 is an apocalyptic number.

21043413 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21043413 is a deficient number, since it is larger than the sum of its proper divisors (10875435).

21043413 is a wasteful number, since it uses less digits than its factorization.

21043413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21043413 is about 4587.3099960652. The cubic root of 21043413 is about 276.0824029315.

Adding to 21043413 its reverse (31434012), we get a palindrome (52477425).

The spelling of 21043413 in words is "twenty-one million, forty-three thousand, four hundred thirteen".