21613443 has 24 divisors (see below), whose sum is σ = 31048752. Its totient is φ = 13369344.

The previous prime is 21613441. The next prime is 21613447. The reversal of 21613443 is 34431612.

It is not a de Polignac number, because 21613443 - 2¹ = 21613441 is a prime.

It is a plaindrome in base 11.

It is a zygodrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21613441) 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, 83971 + ... + 84227.

It is an arithmetic number, because the mean of its divisors is an integer number (1293698).

Almost surely, 2^21613443 is an apocalyptic number.

21613443 is a deficient number, since it is larger than the sum of its proper divisors (9435309).

21613443 is a wasteful number, since it uses less digits than its factorization.

21613443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391 (or 374 counting only the distinct ones).

The product of its digits is 1728, while the sum is 24.

The square root of 21613443 is about 4649.0260270297. The cubic root of 21613443 is about 278.5530929230.

The spelling of 21613443 in words is "twenty-one million, six hundred thirteen thousand, four hundred forty-three".