21011356 has 6 divisors (see below), whose sum is σ = 36769880. Its totient is φ = 10505676.

The previous prime is 21011327. The next prime is 21011357. The reversal of 21011356 is 65311012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011357) 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 as a sum of consecutive naturals, namely, 2626416 + ... + 2626423.

Almost surely, 2^21011356 is an apocalyptic number.

It is an amenable number.

21011356 is a deficient number, since it is larger than the sum of its proper divisors (15758524).

21011356 is a wasteful number, since it uses less digits than its factorization.

21011356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5252843 (or 5252841 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21011356 is about 4583.8145686753. The cubic root of 21011356 is about 275.9421393797.

Adding to 21011356 its reverse (65311012), we get a palindrome (86322368).

The spelling of 21011356 in words is "twenty-one million, eleven thousand, three hundred fifty-six".