21139012 has 6 divisors (see below), whose sum is σ = 36993278. Its totient is φ = 10569504.

The previous prime is 21139009. The next prime is 21139031. The reversal of 21139012 is 21093112.

It can be written as a sum of positive squares in only one way, i.e., 19660356 + 1478656 = 4434^2 + 1216^2 .

It is a super-2 number, since 2×21139012² = 893715656672288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2642373 + ... + 2642380.

Almost surely, 2^21139012 is an apocalyptic number.

It is an amenable number.

21139012 is a deficient number, since it is larger than the sum of its proper divisors (15854266).

21139012 is a wasteful number, since it uses less digits than its factorization.

21139012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5284757 (or 5284755 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21139012 is about 4597.7181296813. The cubic root of 21139012 is about 276.4998468542.

The spelling of 21139012 in words is "twenty-one million, one hundred thirty-nine thousand, twelve".