21120517 has 16 divisors (see below), whose sum is σ = 23975424. Its totient is φ = 18432000.

The previous prime is 21120503. The next prime is 21120523. The reversal of 21120517 is 71502112.

21120517 is nontrivially palindromic in base 4.

It is a cyclic number.

It is not a de Polignac number, because 21120517 - 2²³ = 12731909 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120494 and 21120503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82053 + ... + 82309.

It is an arithmetic number, because the mean of its divisors is an integer number (1498464).

Almost surely, 2^21120517 is an apocalyptic number.

It is an amenable number.

21120517 is a deficient number, since it is larger than the sum of its proper divisors (2854907).

21120517 is a wasteful number, since it uses less digits than its factorization.

21120517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21120517 is about 4595.7063657288. The cubic root of 21120517 is about 276.4191846674.

Adding to 21120517 its reverse (71502112), we get a palindrome (92622629).

The spelling of 21120517 in words is "twenty-one million, one hundred twenty thousand, five hundred seventeen".