21124834 has 4 divisors (see below), whose sum is σ = 31687254. Its totient is φ = 10562416.

The previous prime is 21124823. The next prime is 21124841. The reversal of 21124834 is 43842112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15578809 + 5546025 = 3947^2 + 2355^2 .

It is a super-2 number, since 2×21124834² = 892517223055112, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21124799 and 21124808.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5281207 + ... + 5281210.

Almost surely, 2^21124834 is an apocalyptic number.

21124834 is a deficient number, since it is larger than the sum of its proper divisors (10562420).

21124834 is a wasteful number, since it uses less digits than its factorization.

21124834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10562419.

The product of its digits is 1536, while the sum is 25.

The square root of 21124834 is about 4596.1760192577. The cubic root of 21124834 is about 276.4380165979.

Adding to 21124834 its reverse (43842112), we get a palindrome (64966946).

The spelling of 21124834 in words is "twenty-one million, one hundred twenty-four thousand, eight hundred thirty-four".