21158850291921 has 32 divisors (see below), whose sum is σ = 32281256448000. Its totient is φ = 13691287728144.

The previous prime is 21158850291899. The next prime is 21158850291923. The reversal of 21158850291921 is 12919205885112.

It is a happy number.

21158850291921 is a `hidden beast` number, since 2 + 1 + 1 + 588 + 5 + 0 + 29 + 19 + 21 = 666.

It is not a de Polignac number, because 21158850291921 - 2¹³ = 21158850283729 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21158850291923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 83939925 + ... + 84191618.

It is an arithmetic number, because the mean of its divisors is an integer number (1008789264000).

Almost surely, 2^{21158850291921} is an apocalyptic number.

It is an amenable number.

21158850291921 is a deficient number, since it is larger than the sum of its proper divisors (11122406156079).

21158850291921 is a wasteful number, since it uses less digits than its factorization.

21158850291921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168131690 (or 168131684 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 54.

The spelling of 21158850291921 in words is "twenty-one trillion, one hundred fifty-eight billion, eight hundred fifty million, two hundred ninety-one thousand, nine hundred twenty-one".