21820013253 has 8 divisors (see below), whose sum is σ = 32325945600. Its totient is φ = 14546675484.

The previous prime is 21820013251. The next prime is 21820013263. The reversal of 21820013253 is 35231002812.

It is not a de Polignac number, because 21820013253 - 2¹ = 21820013251 is a prime.

It is a super-2 number, since 2×21820013253² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 808148639 = 21820013253 / (2 + 1 + 8 + 2 + 0 + 0 + 1 + 3 + 2 + 5 + 3).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21820013251) 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 7 ways as a sum of consecutive naturals, for example, 404074293 + ... + 404074346.

It is an arithmetic number, because the mean of its divisors is an integer number (4040743200).

Almost surely, 2^21820013253 is an apocalyptic number.

It is an amenable number.

21820013253 is a deficient number, since it is larger than the sum of its proper divisors (10505932347).

21820013253 is an equidigital number, since it uses as much as digits as its factorization.

21820013253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 808148648 (or 808148642 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 21820013253 in words is "twenty-one billion, eight hundred twenty million, thirteen thousand, two hundred fifty-three".