21081752 has 16 divisors (see below), whose sum is σ = 39615000. Its totient is φ = 10517760.

The previous prime is 21081737. The next prime is 21081761. The reversal of 21081752 is 25718012.

It is a congruent number.

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 in 3 ways as a sum of consecutive naturals, for example, 1352 + ... + 6632.

Almost surely, 2^21081752 is an apocalyptic number.

It is an amenable number.

21081752 is a deficient number, since it is larger than the sum of its proper divisors (18533248).

21081752 is a wasteful number, since it uses less digits than its factorization.

21081752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5786 (or 5782 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21081752 is about 4591.4869051321. The cubic root of 21081752 is about 276.2499660804.

Adding to 21081752 its reverse (25718012), we get a palindrome (46799764).

The spelling of 21081752 in words is "twenty-one million, eighty-one thousand, seven hundred fifty-two".