21215771115016 has 16 divisors (see below), whose sum is σ = 39781816890300. Its totient is φ = 10607286610944.

The previous prime is 21215771114987. The next prime is 21215771115031. The reversal of 21215771115016 is 61051117751212.

It can be written as a sum of positive squares in 2 ways, for example, as 16243076272900 + 4972694842116 = 4030270^2 + 2229954^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21215771115016.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74717761 + ... + 75001168.

Almost surely, 2^{21215771115016} is an apocalyptic number.

It is an amenable number.

21215771115016 is a deficient number, since it is larger than the sum of its proper divisors (18566045775284).

21215771115016 is a wasteful number, since it uses less digits than its factorization.

21215771115016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149736648 (or 149736644 counting only the distinct ones).

The product of its (nonzero) digits is 29400, while the sum is 40.

Adding to 21215771115016 its reverse (61051117751212), we get a palindrome (82266888866228).

The spelling of 21215771115016 in words is "twenty-one trillion, two hundred fifteen billion, seven hundred seventy-one million, one hundred fifteen thousand, sixteen".