21105477852 has 12 divisors (see below), whose sum is σ = 49246115016. Its totient is φ = 7035159280.

The previous prime is 21105477851. The next prime is 21105477857. The reversal of 21105477852 is 25877450112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21105477852² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105477851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 879394899 + ... + 879394922.

It is an arithmetic number, because the mean of its divisors is an integer number (4103842918).

Almost surely, 2^21105477852 is an apocalyptic number.

It is an amenable number.

21105477852 is an abundant number, since it is smaller than the sum of its proper divisors (28140637164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21105477852 is a wasteful number, since it uses less digits than its factorization.

21105477852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1758789828 (or 1758789826 counting only the distinct ones).

The product of its (nonzero) digits is 156800, while the sum is 42.

The spelling of 21105477852 in words is "twenty-one billion, one hundred five million, four hundred seventy-seven thousand, eight hundred fifty-two".