21555252223 has 4 divisors (see below), whose sum is σ = 21710326120. Its totient is φ = 21400178328.

The previous prime is 21555252167. The next prime is 21555252233. The reversal of 21555252223 is 32225255512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21555252223 - 2²⁹ = 21018381311 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 (21555252233) 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 3 ways as a sum of consecutive naturals, for example, 77536740 + ... + 77537017.

It is an arithmetic number, because the mean of its divisors is an integer number (5427581530).

Almost surely, 2^21555252223 is an apocalyptic number.

21555252223 is a deficient number, since it is larger than the sum of its proper divisors (155073897).

21555252223 is a wasteful number, since it uses less digits than its factorization.

21555252223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155073896.

The product of its digits is 60000, while the sum is 34.

The spelling of 21555252223 in words is "twenty-one billion, five hundred fifty-five million, two hundred fifty-two thousand, two hundred twenty-three".