21050756 has 6 divisors (see below), whose sum is σ = 36838830. Its totient is φ = 10525376.

The previous prime is 21050749. The next prime is 21050801. The reversal of 21050756 is 65705012.

It can be written as a sum of positive squares in only one way, i.e., 17774656 + 3276100 = 4216^2 + 1810^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2631341 + ... + 2631348.

It is an arithmetic number, because the mean of its divisors is an integer number (6139805).

Almost surely, 2^21050756 is an apocalyptic number.

It is an amenable number.

21050756 is a deficient number, since it is larger than the sum of its proper divisors (15788074).

21050756 is a wasteful number, since it uses less digits than its factorization.

21050756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5262693 (or 5262691 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 21050756 is about 4588.1102863815. The cubic root of 21050756 is about 276.1145117490.

Adding to 21050756 its reverse (65705012), we get a palindrome (86755768).

The spelling of 21050756 in words is "twenty-one million, fifty thousand, seven hundred fifty-six".