21212636553 has 12 divisors (see below), whose sum is σ = 30642958320. Its totient is φ = 14140611576.

The previous prime is 21212636527. The next prime is 21212636563. The reversal of 21212636553 is 35563621212.

21212636553 is a `hidden beast` number, since 2 + 1 + 2 + 12 + 636 + 5 + 5 + 3 = 666.

It is not a de Polignac number, because 21212636553 - 2⁵ = 21212636521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21212636563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30450 + ... + 208212.

It is an arithmetic number, because the mean of its divisors is an integer number (2553579860).

Almost surely, 2^21212636553 is an apocalyptic number.

It is an amenable number.

21212636553 is a deficient number, since it is larger than the sum of its proper divisors (9430321767).

21212636553 is a wasteful number, since it uses less digits than its factorization.

21212636553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191028 (or 191025 counting only the distinct ones).

The product of its digits is 64800, while the sum is 36.

The spelling of 21212636553 in words is "twenty-one billion, two hundred twelve million, six hundred thirty-six thousand, five hundred fifty-three".