21138845291 has 8 divisors (see below), whose sum is σ = 21800258304. Its totient is φ = 20482174080.

The previous prime is 21138845263. The next prime is 21138845309. The reversal of 21138845291 is 19254883112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21138845291 - 2¹⁰ = 21138844267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21138845491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1176395 + ... + 1194228.

It is an arithmetic number, because the mean of its divisors is an integer number (2725032288).

Almost surely, 2^21138845291 is an apocalyptic number.

21138845291 is a deficient number, since it is larger than the sum of its proper divisors (661413013).

21138845291 is a wasteful number, since it uses less digits than its factorization.

21138845291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2370901.

The product of its digits is 138240, while the sum is 44.

The spelling of 21138845291 in words is "twenty-one billion, one hundred thirty-eight million, eight hundred forty-five thousand, two hundred ninety-one".