21751072 has 24 divisors (see below), whose sum is σ = 48940416. Its totient is φ = 9321792.

The previous prime is 21751069. The next prime is 21751087. The reversal of 21751072 is 27015712.

It is a happy number.

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, 48328 + ... + 48775.

It is an arithmetic number, because the mean of its divisors is an integer number (2039184).

Almost surely, 2^21751072 is an apocalyptic number.

It is an amenable number.

21751072 is an abundant number, since it is smaller than the sum of its proper divisors (27189344).

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

21751072 is an equidigital number, since it uses as much as digits as its factorization.

21751072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97120 (or 97112 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 21751072 is about 4663.8044555920. The cubic root of 21751072 is about 279.1430945073.

Adding to 21751072 its reverse (27015712), we get a palindrome (48766784).

The spelling of 21751072 in words is "twenty-one million, seven hundred fifty-one thousand, seventy-two".