21221546636636 has 24 divisors (see below), whose sum is σ = 37336616467920. Its totient is φ = 10553971928192.

The previous prime is 21221546636627. The next prime is 21221546636651. The reversal of 21221546636636 is 63663664512212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 916406 + ... + 6578973.

It is an arithmetic number, because the mean of its divisors is an integer number (1555692352830).

Almost surely, 2^{21221546636636} is an apocalyptic number.

It is an amenable number.

21221546636636 is a deficient number, since it is larger than the sum of its proper divisors (16115069831284).

21221546636636 is a wasteful number, since it uses less digits than its factorization.

21221546636636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7499173 (or 7499171 counting only the distinct ones).

The product of its digits is 11197440, while the sum is 53.

The spelling of 21221546636636 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred forty-six million, six hundred thirty-six thousand, six hundred thirty-six".