21751012 has 6 divisors (see below), whose sum is σ = 38064278. Its totient is φ = 10875504.

The previous prime is 21750997. The next prime is 21751019. The reversal of 21751012 is 21015712.

It can be written as a sum of positive squares in only one way, i.e., 21307456 + 443556 = 4616^2 + 666^2 .

It is not an unprimeable number, because it can be changed into a prime (21751019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2718873 + ... + 2718880.

Almost surely, 2^21751012 is an apocalyptic number.

It is an amenable number.

21751012 is a deficient number, since it is larger than the sum of its proper divisors (16313266).

21751012 is a wasteful number, since it uses less digits than its factorization.

21751012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5437757 (or 5437755 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21751012 is about 4663.7980230709. The cubic root of 21751012 is about 279.1428378364.

Adding to 21751012 its reverse (21015712), we get a palindrome (42766724).

The spelling of 21751012 in words is "twenty-one million, seven hundred fifty-one thousand, twelve".