21516293 has 8 divisors (see below), whose sum is σ = 22543488. Its totient is φ = 20496784.

The previous prime is 21516281. The next prime is 21516301. The reversal of 21516293 is 39261512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21516293 is a prime.

It is a super-3 number, since 3×21516293³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21516233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4271 + ... + 7827.

It is an arithmetic number, because the mean of its divisors is an integer number (2817936).

Almost surely, 2^21516293 is an apocalyptic number.

21516293 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21516293 is a deficient number, since it is larger than the sum of its proper divisors (1027195).

21516293 is a wasteful number, since it uses less digits than its factorization.

21516293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3843.

The product of its digits is 3240, while the sum is 29.

The square root of 21516293 is about 4638.5658343932. The cubic root of 21516293 is about 278.1351110746.

The spelling of 21516293 in words is "twenty-one million, five hundred sixteen thousand, two hundred ninety-three".