21140404 has 24 divisors (see below), whose sum is σ = 39247488. Its totient is φ = 9942240.

The previous prime is 21140389. The next prime is 21140423. The reversal of 21140404 is 40404112.

It is a plaindrome in base 7.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 3729 + ... + 7495.

It is an arithmetic number, because the mean of its divisors is an integer number (1635312).

Almost surely, 2^21140404 is an apocalyptic number.

It is an amenable number.

21140404 is a deficient number, since it is larger than the sum of its proper divisors (18107084).

21140404 is a wasteful number, since it uses less digits than its factorization.

21140404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3855 (or 3853 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21140404 is about 4597.8695066302. The cubic root of 21140404 is about 276.5059158755.

Adding to 21140404 its reverse (40404112), we get a palindrome (61544516).

The spelling of 21140404 in words is "twenty-one million, one hundred forty thousand, four hundred four".