21317458 has 32 divisors (see below), whose sum is σ = 34836480. Its totient is φ = 9757440.

The previous prime is 21317447. The next prime is 21317479. The reversal of 21317458 is 85471312.

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 15 ways as a sum of consecutive naturals, for example, 167791 + ... + 167917.

It is an arithmetic number, because the mean of its divisors is an integer number (1088640).

Almost surely, 2^21317458 is an apocalyptic number.

21317458 is a deficient number, since it is larger than the sum of its proper divisors (13519022).

21317458 is a wasteful number, since it uses less digits than its factorization.

21317458 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282.

The product of its digits is 6720, while the sum is 31.

The square root of 21317458 is about 4617.0832784346. The cubic root of 21317458 is about 277.2756967848.

It can be divided in two parts, 213 and 17458, that added together give a palindrome (17671).

The spelling of 21317458 in words is "twenty-one million, three hundred seventeen thousand, four hundred fifty-eight".