21003356 has 24 divisors (see below), whose sum is σ = 40216176. Its totient is φ = 9518720.

The previous prime is 21003349. The next prime is 21003371. The reversal of 21003356 is 65330012.

It is a super-2 number, since 2×21003356² = 882281926525472, which contains 22 as substring.

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, 24080 + ... + 24936.

It is an arithmetic number, because the mean of its divisors is an integer number (1675674).

Almost surely, 2^21003356 is an apocalyptic number.

It is an amenable number.

21003356 is a deficient number, since it is larger than the sum of its proper divisors (19212820).

21003356 is a wasteful number, since it uses less digits than its factorization.

21003356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1429 (or 1427 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 21003356 is about 4582.9418499475. The cubic root of 21003356 is about 275.9071136006.

Adding to 21003356 its reverse (65330012), we get a palindrome (86333368).

The spelling of 21003356 in words is "twenty-one million, three thousand, three hundred fifty-six".