21261304 has 32 divisors (see below), whose sum is σ = 42310800. Its totient is φ = 9987840.

The previous prime is 21261293. The next prime is 21261337. The reversal of 21261304 is 40316212.

It is a Harshad number since it is a multiple of its sum of digits (19).

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, 20314 + ... + 21334.

Almost surely, 2^21261304 is an apocalyptic number.

It is an amenable number.

21261304 is a deficient number, since it is larger than the sum of its proper divisors (21049496).

21261304 is a wasteful number, since it uses less digits than its factorization.

21261304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183 (or 1179 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21261304 is about 4610.9981565817. The cubic root of 21261304 is about 277.0320180899.

Adding to 21261304 its reverse (40316212), we get a palindrome (61577516).

It can be divided in two parts, 212 and 61304, that added together give a palindrome (61516).

The spelling of 21261304 in words is "twenty-one million, two hundred sixty-one thousand, three hundred four".