21049550291 has 24 divisors (see below), whose sum is σ = 26721004464. Its totient is φ = 16396860480.

The previous prime is 21049550279. The next prime is 21049550317. The reversal of 21049550291 is 19205594012.

It is not a de Polignac number, because 21049550291 - 2⁶ = 21049550227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21049550261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2676521 + ... + 2684373.

It is an arithmetic number, because the mean of its divisors is an integer number (1113375186).

Almost surely, 2^21049550291 is an apocalyptic number.

21049550291 is a deficient number, since it is larger than the sum of its proper divisors (5671454173).

21049550291 is a wasteful number, since it uses less digits than its factorization.

21049550291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12851 (or 12844 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 21049550291 in words is "twenty-one billion, forty-nine million, five hundred fifty thousand, two hundred ninety-one".