21150511211171 has 16 divisors (see below), whose sum is σ = 22193284089600. Its totient is φ = 20128771504800.

The previous prime is 21150511211161. The next prime is 21150511211177. The reversal of 21150511211171 is 17111211505112.

It is a cyclic number.

It is not a de Polignac number, because 21150511211171 - 2²² = 21150507016867 is a prime.

It is a super-2 number, since 2×21150511211171² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21150511211177) 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 15 ways as a sum of consecutive naturals, for example, 7450760 + ... + 9890138.

It is an arithmetic number, because the mean of its divisors is an integer number (1387080255600).

Almost surely, 2^{21150511211171} is an apocalyptic number.

21150511211171 is a deficient number, since it is larger than the sum of its proper divisors (1042772878429).

21150511211171 is a wasteful number, since it uses less digits than its factorization.

21150511211171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2443690.

The product of its (nonzero) digits is 700, while the sum is 29.

Adding to 21150511211171 its reverse (17111211505112), we get a palindrome (38261722716283).

The spelling of 21150511211171 in words is "twenty-one trillion, one hundred fifty billion, five hundred eleven million, two hundred eleven thousand, one hundred seventy-one".