21005844375852 has 108 divisors (see below), whose sum is σ = 63759675260736. Its totient is φ = 5808067554240.

The previous prime is 21005844375749. The next prime is 21005844375853. The reversal of 21005844375852 is 25857344850012.

It is a happy number.

21005844375852 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 58 + 4 + 4 + 3 + 7 + 585 + 2 = 666.

It is not an unprimeable number, because it can be changed into a prime (21005844375853) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 192011043 + ... + 192120410.

Almost surely, 2^{21005844375852} is an apocalyptic number.

It is an amenable number.

21005844375852 is an abundant number, since it is smaller than the sum of its proper divisors (42753830884884).

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

21005844375852 is a wasteful number, since it uses less digits than its factorization.

21005844375852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384131508 (or 384131496 counting only the distinct ones).

The product of its (nonzero) digits is 10752000, while the sum is 54.

The spelling of 21005844375852 in words is "twenty-one trillion, five billion, eight hundred forty-four million, three hundred seventy-five thousand, eight hundred fifty-two".