21550539 has 8 divisors (see below), whose sum is σ = 29510800. Its totient is φ = 13978656.

The previous prime is 21550537. The next prime is 21550547. The reversal of 21550539 is 93505512.

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

It is not a de Polignac number, because 21550539 - 2¹ = 21550537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21550537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96964 + ... + 97185.

It is an arithmetic number, because the mean of its divisors is an integer number (3688850).

Almost surely, 2^21550539 is an apocalyptic number.

21550539 is a deficient number, since it is larger than the sum of its proper divisors (7960261).

21550539 is a wasteful number, since it uses less digits than its factorization.

21550539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194189.

The product of its (nonzero) digits is 6750, while the sum is 30.

The square root of 21550539 is about 4642.2558094099. The cubic root of 21550539 is about 278.2825956814.

The spelling of 21550539 in words is "twenty-one million, five hundred fifty thousand, five hundred thirty-nine".