21165205443412 has 24 divisors (see below), whose sum is σ = 37115540693280. Its totient is φ = 10560766403040.

The previous prime is 21165205443391. The next prime is 21165205443497. The reversal of 21165205443412 is 21434450256112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86287639 + ... + 86532577.

It is an arithmetic number, because the mean of its divisors is an integer number (1546480862220).

Almost surely, 2^{21165205443412} is an apocalyptic number.

It is an amenable number.

21165205443412 is a deficient number, since it is larger than the sum of its proper divisors (15950335249868).

21165205443412 is a wasteful number, since it uses less digits than its factorization.

21165205443412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289431 (or 289429 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 40.

Adding to 21165205443412 its reverse (21434450256112), we get a palindrome (42599655699524).

The spelling of 21165205443412 in words is "twenty-one trillion, one hundred sixty-five billion, two hundred five million, four hundred forty-three thousand, four hundred twelve".