21117534 has 8 divisors (see below), whose sum is σ = 42235080. Its totient is φ = 7039176.

The previous prime is 21117521. The next prime is 21117557. The reversal of 21117534 is 43571112.

It is a sphenic number, since it is the product of 3 distinct primes.

21117534 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1759789 + ... + 1759800.

It is an arithmetic number, because the mean of its divisors is an integer number (5279385).

Almost surely, 2^21117534 is an apocalyptic number.

21117534 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21117534 is a wasteful number, since it uses less digits than its factorization.

21117534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3519594.

The product of its digits is 840, while the sum is 24.

The square root of 21117534 is about 4595.3818122110. The cubic root of 21117534 is about 276.4061705092.

Adding to 21117534 its reverse (43571112), we get a palindrome (64688646).

The spelling of 21117534 in words is "twenty-one million, one hundred seventeen thousand, five hundred thirty-four".