21305522253 has 8 divisors (see below), whose sum is σ = 28415579968. Its totient is φ = 14199573024.

The previous prime is 21305522239. The next prime is 21305522261. The reversal of 21305522253 is 35222550312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21305522253 - 2¹⁴ = 21305505869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21305522253.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305522233) 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 7 ways as a sum of consecutive naturals, for example, 1015000 + ... + 1035777.

It is an arithmetic number, because the mean of its divisors is an integer number (3551947496).

Almost surely, 2^21305522253 is an apocalyptic number.

It is an amenable number.

21305522253 is a deficient number, since it is larger than the sum of its proper divisors (7110057715).

21305522253 is a wasteful number, since it uses less digits than its factorization.

21305522253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2054243.

The product of its (nonzero) digits is 18000, while the sum is 30.

The spelling of 21305522253 in words is "twenty-one billion, three hundred five million, five hundred twenty-two thousand, two hundred fifty-three".