21917043 has 12 divisors (see below), whose sum is σ = 31861648. Its totient is φ = 14517360.

The previous prime is 21917023. The next prime is 21917113. The reversal of 21917043 is 34071912.

It is not a de Polignac number, because 21917043 - 2¹³ = 21908851 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21916998 and 21917016.

It is not an unprimeable number, because it can be changed into a prime (21917003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6343 + ... + 9168.

Almost surely, 2^21917043 is an apocalyptic number.

21917043 is a deficient number, since it is larger than the sum of its proper divisors (9944605).

21917043 is a wasteful number, since it uses less digits than its factorization.

21917043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15674 (or 15671 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21917043 is about 4681.5641616878. The cubic root of 21917043 is about 279.8512943370.

Adding to 21917043 its reverse (34071912), we get a palindrome (55988955).

The spelling of 21917043 in words is "twenty-one million, nine hundred seventeen thousand, forty-three".