21005253113 has 16 divisors (see below), whose sum is σ = 23124788736. Its totient is φ = 18958484160.

The previous prime is 21005253107. The next prime is 21005253161. The reversal of 21005253113 is 31135250012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21005253113 - 2¹⁰ = 21005252089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21005253163) 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, 633323 + ... + 665663.

It is an arithmetic number, because the mean of its divisors is an integer number (1445299296).

Almost surely, 2^21005253113 is an apocalyptic number.

It is an amenable number.

21005253113 is a deficient number, since it is larger than the sum of its proper divisors (2119535623).

21005253113 is a wasteful number, since it uses less digits than its factorization.

21005253113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33464.

The product of its (nonzero) digits is 900, while the sum is 23.

The spelling of 21005253113 in words is "twenty-one billion, five million, two hundred fifty-three thousand, one hundred thirteen".