21373418 has 16 divisors (see below), whose sum is σ = 35324640. Its totient is φ = 9618000.

The previous prime is 21373411. The next prime is 21373447. The reversal of 21373418 is 81437312.

It is not an unprimeable number, because it can be changed into a prime (21373411) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2588 + ... + 7031.

It is an arithmetic number, because the mean of its divisors is an integer number (2207790).

Almost surely, 2^21373418 is an apocalyptic number.

21373418 is a deficient number, since it is larger than the sum of its proper divisors (13951222).

21373418 is a wasteful number, since it uses less digits than its factorization.

21373418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9733.

The product of its digits is 4032, while the sum is 29.

The square root of 21373418 is about 4623.1394095355. The cubic root of 21373418 is about 277.5181082791.

It can be divided in two parts, 2137 and 3418, that added together give a palindrome (5555).

The spelling of 21373418 in words is "twenty-one million, three hundred seventy-three thousand, four hundred eighteen".