21125734 has 8 divisors (see below), whose sum is σ = 36215568. Its totient is φ = 9053880.

The previous prime is 21125729. The next prime is 21125737. The reversal of 21125734 is 43752112.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21125699 and 21125708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 754477 + ... + 754504.

It is an arithmetic number, because the mean of its divisors is an integer number (4526946).

Almost surely, 2^21125734 is an apocalyptic number.

21125734 is a deficient number, since it is larger than the sum of its proper divisors (15089834).

21125734 is a wasteful number, since it uses less digits than its factorization.

21125734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1508990.

The product of its digits is 1680, while the sum is 25.

The square root of 21125734 is about 4596.2739256924. The cubic root of 21125734 is about 276.4419423200.

Adding to 21125734 its reverse (43752112), we get a palindrome (64877846).

The spelling of 21125734 in words is "twenty-one million, one hundred twenty-five thousand, seven hundred thirty-four".