21005134 has 8 divisors (see below), whose sum is σ = 31625640. Its totient is φ = 10463256.

The previous prime is 21005129. The next prime is 21005143. The reversal of 21005134 is 43150012.

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, 18984 + ... + 20059.

It is an arithmetic number, because the mean of its divisors is an integer number (3953205).

Almost surely, 2^21005134 is an apocalyptic number.

21005134 is a deficient number, since it is larger than the sum of its proper divisors (10620506).

21005134 is a wasteful number, since it uses less digits than its factorization.

21005134 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39314.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21005134 is about 4583.1358260475. The cubic root of 21005134 is about 275.9148988486.

Adding to 21005134 its reverse (43150012), we get a palindrome (64155146).

The spelling of 21005134 in words is "twenty-one million, five thousand, one hundred thirty-four".