21155165212141 has 4 divisors (see below), whose sum is σ = 21156141340732. Its totient is φ = 21154189083552.

The previous prime is 21155165212121. The next prime is 21155165212193. The reversal of 21155165212141 is 14121256155112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11092756475241 + 10062408736900 = 3330579^2 + 3172130^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155165212141 - 2¹⁵ = 21155165179373 is a prime.

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 21155165212141.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155165212121) 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, 488031786 + ... + 488075131.

It is an arithmetic number, because the mean of its divisors is an integer number (5289035335183).

Almost surely, 2^{21155165212141} is an apocalyptic number.

It is an amenable number.

21155165212141 is a deficient number, since it is larger than the sum of its proper divisors (976128591).

21155165212141 is an equidigital number, since it uses as much as digits as its factorization.

21155165212141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 976128590.

The product of its digits is 24000, while the sum is 37.

The spelling of 21155165212141 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred sixty-five million, two hundred twelve thousand, one hundred forty-one".