21983557 has 8 divisors (see below), whose sum is σ = 22763520. Its totient is φ = 21208080.

The previous prime is 21983531. The next prime is 21983569. The reversal of 21983557 is 75538912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21983557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21983597) 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, 11148 + ... + 12970.

It is an arithmetic number, because the mean of its divisors is an integer number (2845440).

Almost surely, 2^21983557 is an apocalyptic number.

It is an amenable number.

21983557 is a deficient number, since it is larger than the sum of its proper divisors (779963).

21983557 is a wasteful number, since it uses less digits than its factorization.

21983557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2243.

The product of its digits is 75600, while the sum is 40.

The square root of 21983557 is about 4688.6626024912. The cubic root of 21983557 is about 280.1341066774.

The spelling of 21983557 in words is "twenty-one million, nine hundred eighty-three thousand, five hundred fifty-seven".