21143208291 has 8 divisors (see below), whose sum is σ = 28611705024. Its totient is φ = 13885091880.

The previous prime is 21143208277. The next prime is 21143208299. The reversal of 21143208291 is 19280234112.

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

It is not a de Polignac number, because 21143208291 - 2⁵ = 21143208259 is a prime.

It is a super-2 number, since 2×21143208291² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21143208299) 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, 52594845 + ... + 52595246.

It is an arithmetic number, because the mean of its divisors is an integer number (3576463128).

Almost surely, 2^21143208291 is an apocalyptic number.

21143208291 is a deficient number, since it is larger than the sum of its proper divisors (7468496733).

21143208291 is a wasteful number, since it uses less digits than its factorization.

21143208291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105190161.

The product of its (nonzero) digits is 6912, while the sum is 33.

The spelling of 21143208291 in words is "twenty-one billion, one hundred forty-three million, two hundred eight thousand, two hundred ninety-one".