21534017 has 4 divisors (see below), whose sum is σ = 21563076. Its totient is φ = 21504960.

The previous prime is 21533999. The next prime is 21534031. The reversal of 21534017 is 71043512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 703921 + 20830096 = 839^2 + 4564^2 .

It is a cyclic number.

It is not a de Polignac number, because 21534017 - 2²⁰ = 20485441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21533983 and 21534001.

It is not an unprimeable number, because it can be changed into a prime (21534047) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13388 + ... + 14909.

It is an arithmetic number, because the mean of its divisors is an integer number (5390769).

Almost surely, 2^21534017 is an apocalyptic number.

It is an amenable number.

21534017 is a deficient number, since it is larger than the sum of its proper divisors (29059).

21534017 is an equidigital number, since it uses as much as digits as its factorization.

21534017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29058.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21534017 is about 4640.4759454177. The cubic root of 21534017 is about 278.2114611802.

Adding to 21534017 its reverse (71043512), we get a palindrome (92577529).

The spelling of 21534017 in words is "twenty-one million, five hundred thirty-four thousand, seventeen".