21255562349 has 32 divisors (see below), whose sum is σ = 26132520960. Its totient is φ = 16875101952.

The previous prime is 21255562291. The next prime is 21255562387. The reversal of 21255562349 is 94326555212.

It is a happy number.

It is not a de Polignac number, because 21255562349 - 2²⁰ = 21254513773 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255562049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1992572 + ... + 2003210.

It is an arithmetic number, because the mean of its divisors is an integer number (816641280).

Almost surely, 2^21255562349 is an apocalyptic number.

It is an amenable number.

21255562349 is a deficient number, since it is larger than the sum of its proper divisors (4876958611).

21255562349 is a wasteful number, since it uses less digits than its factorization.

21255562349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10929.

The product of its digits is 648000, while the sum is 44.

The spelling of 21255562349 in words is "twenty-one billion, two hundred fifty-five million, five hundred sixty-two thousand, three hundred forty-nine".