21251442211516 has 24 divisors (see below), whose sum is σ = 40571686431360. Its totient is φ = 9659567578800.

The previous prime is 21251442211501. The next prime is 21251442211543. The reversal of 21251442211516 is 61511224415212.

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 7 ways as a sum of consecutive naturals, for example, 2054296 + ... + 6835423.

It is an arithmetic number, because the mean of its divisors is an integer number (1690486934640).

Almost surely, 2^{21251442211516} is an apocalyptic number.

It is an amenable number.

21251442211516 is a deficient number, since it is larger than the sum of its proper divisors (19320244219844).

21251442211516 is a wasteful number, since it uses less digits than its factorization.

21251442211516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8944065 (or 8944063 counting only the distinct ones).

The product of its digits is 38400, while the sum is 37.

Adding to 21251442211516 its reverse (61511224415212), we get a palindrome (82762666626728).

The spelling of 21251442211516 in words is "twenty-one trillion, two hundred fifty-one billion, four hundred forty-two million, two hundred eleven thousand, five hundred sixteen".