21717055 has 8 divisors (see below), whose sum is σ = 26615232. Its totient is φ = 17003808.

The previous prime is 21717043. The next prime is 21717061. The reversal of 21717055 is 55071712.

21717055 = 1900² + 1901² + ... + 1905².

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 21717055 - 2⁷ = 21716927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 45972 + ... + 46441.

It is an arithmetic number, because the mean of its divisors is an integer number (3326904).

Almost surely, 2^21717055 is an apocalyptic number.

21717055 is a deficient number, since it is larger than the sum of its proper divisors (4898177).

21717055 is an equidigital number, since it uses as much as digits as its factorization.

21717055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92465.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 21717055 is about 4660.1561132649. The cubic root of 21717055 is about 278.9974991533.

Adding to 21717055 its reverse (55071712), we get a palindrome (76788767).

The spelling of 21717055 in words is "twenty-one million, seven hundred seventeen thousand, fifty-five".