21261033121144 has 16 divisors (see below), whose sum is σ = 39864486160800. Its totient is φ = 10630503478272.

The previous prime is 21261033121103. The next prime is 21261033121169. The reversal of 21261033121144 is 44112133016212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11171569 + ... + 12935455.

It is an arithmetic number, because the mean of its divisors is an integer number (2491530385050).

Almost surely, 2^{21261033121144} is an apocalyptic number.

It is an amenable number.

21261033121144 is a deficient number, since it is larger than the sum of its proper divisors (18603453039656).

21261033121144 is a wasteful number, since it uses less digits than its factorization.

21261033121144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3270582 (or 3270578 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

Adding to 21261033121144 its reverse (44112133016212), we get a palindrome (65373166137356).

The spelling of 21261033121144 in words is "twenty-one trillion, two hundred sixty-one billion, thirty-three million, one hundred twenty-one thousand, one hundred forty-four".