21049539 has 8 divisors (see below), whose sum is σ = 32075520. Its totient is φ = 12028296.

The previous prime is 21049517. The next prime is 21049541. The reversal of 21049539 is 93594012.

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

It is not a de Polignac number, because 21049539 - 2⁹ = 21049027 is a prime.

It is a super-2 number, since 2×21049539² = 886166184225042, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21049939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 501159 + ... + 501200.

It is an arithmetic number, because the mean of its divisors is an integer number (4009440).

Almost surely, 2^21049539 is an apocalyptic number.

21049539 is a deficient number, since it is larger than the sum of its proper divisors (11025981).

21049539 is a wasteful number, since it uses less digits than its factorization.

21049539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1002369.

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 21049539 is about 4587.9776590563. The cubic root of 21049539 is about 276.1091906759.

The spelling of 21049539 in words is "twenty-one million, forty-nine thousand, five hundred thirty-nine".