21555527653 has 16 divisors (see below), whose sum is σ = 24460450560. Its totient is φ = 18815630400.

The previous prime is 21555527641. The next prime is 21555527659. The reversal of 21555527653 is 35672555512.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21555527653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555527659) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128925 + ... + 244402.

It is an arithmetic number, because the mean of its divisors is an integer number (1528778160).

Almost surely, 2^21555527653 is an apocalyptic number.

It is an amenable number.

21555527653 is a deficient number, since it is larger than the sum of its proper divisors (2904922907).

21555527653 is a wasteful number, since it uses less digits than its factorization.

21555527653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373548.

The product of its digits is 1575000, while the sum is 46.

The spelling of 21555527653 in words is "twenty-one billion, five hundred fifty-five million, five hundred twenty-seven thousand, six hundred fifty-three".