21815800253 has 16 divisors (see below), whose sum is σ = 23878901760. Its totient is φ = 19808559936.

The previous prime is 21815800243. The next prime is 21815800297. The reversal of 21815800253 is 35200851812.

It is a cyclic number.

It is not a de Polignac number, because 21815800253 - 2⁶ = 21815800189 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 (21815800243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 599876 + ... + 635202.

It is an arithmetic number, because the mean of its divisors is an integer number (1492431360).

Almost surely, 2^21815800253 is an apocalyptic number.

It is an amenable number.

21815800253 is a deficient number, since it is larger than the sum of its proper divisors (2063101507).

21815800253 is a wasteful number, since it uses less digits than its factorization.

21815800253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36116.

The product of its (nonzero) digits is 19200, while the sum is 35.

The spelling of 21815800253 in words is "twenty-one billion, eight hundred fifteen million, eight hundred thousand, two hundred fifty-three".