21139558 has 8 divisors (see below), whose sum is σ = 34592040. Its totient is φ = 9608880.

The previous prime is 21139513. The next prime is 21139577. The reversal of 21139558 is 85593112.

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

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, 480423 + ... + 480466.

It is an arithmetic number, because the mean of its divisors is an integer number (4324005).

Almost surely, 2^21139558 is an apocalyptic number.

21139558 is a deficient number, since it is larger than the sum of its proper divisors (13452482).

21139558 is a wasteful number, since it uses less digits than its factorization.

21139558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 960902.

The product of its digits is 10800, while the sum is 34.

The square root of 21139558 is about 4597.7775065786. Note that the first 3 decimals coincide. The cubic root of 21139558 is about 276.5022274072.

The spelling of 21139558 in words is "twenty-one million, one hundred thirty-nine thousand, five hundred fifty-eight".