21916757 has 8 divisors (see below), whose sum is σ = 23247000. Its totient is φ = 20591104.

The previous prime is 21916753. The next prime is 21916759. The reversal of 21916757 is 75761912.

It can be written as a sum of positive squares in 4 ways, for example, as 17648401 + 4268356 = 4201^2 + 2066^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21916757 - 2² = 21916753 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21916757.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21916753) 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 in 7 ways as a sum of consecutive naturals, for example, 17219 + ... + 18447.

It is an arithmetic number, because the mean of its divisors is an integer number (2905875).

Almost surely, 2^21916757 is an apocalyptic number.

It is an amenable number.

21916757 is a deficient number, since it is larger than the sum of its proper divisors (1330243).

21916757 is a wasteful number, since it uses less digits than its factorization.

21916757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2295.

The product of its digits is 26460, while the sum is 38.

The square root of 21916757 is about 4681.5336162416. The cubic root of 21916757 is about 279.8500770526.

The spelling of 21916757 in words is "twenty-one million, nine hundred sixteen thousand, seven hundred fifty-seven".