21215041271 has 4 divisors (see below), whose sum is σ = 21732481344. Its totient is φ = 20697601200.

The previous prime is 21215041259. The next prime is 21215041273. The reversal of 21215041271 is 17214051212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21215041271 - 2³⁴ = 4035172087 is a prime.

It is a super-2 number, since 2×21215041271² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21215041271.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215041273) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 258719975 + ... + 258720056.

It is an arithmetic number, because the mean of its divisors is an integer number (5433120336).

Almost surely, 2^21215041271 is an apocalyptic number.

21215041271 is a deficient number, since it is larger than the sum of its proper divisors (517440073).

21215041271 is an equidigital number, since it uses as much as digits as its factorization.

21215041271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517440072.

The product of its (nonzero) digits is 1120, while the sum is 26.

Adding to 21215041271 its reverse (17214051212), we get a palindrome (38429092483).

The spelling of 21215041271 in words is "twenty-one billion, two hundred fifteen million, forty-one thousand, two hundred seventy-one".