21055543636 has 12 divisors (see below), whose sum is σ = 36858558240. Its totient is φ = 10524527000.

The previous prime is 21055543627. The next prime is 21055543657. The reversal of 21055543636 is 63634555012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 796576 + ... + 822583.

It is an arithmetic number, because the mean of its divisors is an integer number (3071546520).

Almost surely, 2^21055543636 is an apocalyptic number.

It is an amenable number.

21055543636 is a deficient number, since it is larger than the sum of its proper divisors (15803014604).

21055543636 is a wasteful number, since it uses less digits than its factorization.

21055543636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1622414 (or 1622412 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 40.

The spelling of 21055543636 in words is "twenty-one billion, fifty-five million, five hundred forty-three thousand, six hundred thirty-six".