21239124 has 12 divisors (see below), whose sum is σ = 49557984. Its totient is φ = 7079704.

The previous prime is 21239087. The next prime is 21239173. The reversal of 21239124 is 42193212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21239124² = 902200776574752, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21239094 and 21239103.

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, 884952 + ... + 884975.

It is an arithmetic number, because the mean of its divisors is an integer number (4129832).

Almost surely, 2^21239124 is an apocalyptic number.

It is an amenable number.

21239124 is an abundant number, since it is smaller than the sum of its proper divisors (28318860).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21239124 is a wasteful number, since it uses less digits than its factorization.

21239124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1769934 (or 1769932 counting only the distinct ones).

The product of its digits is 864, while the sum is 24.

The square root of 21239124 is about 4608.5924098362. The cubic root of 21239124 is about 276.9356504025.

The spelling of 21239124 in words is "twenty-one million, two hundred thirty-nine thousand, one hundred twenty-four".