21216415002061 has 16 divisors (see below), whose sum is σ = 21824206716928. Its totient is φ = 20618373484800.

The previous prime is 21216415002043. The next prime is 21216415002091. The reversal of 21216415002061 is 16020051461212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21216415002061 - 2¹⁵ = 21216414969293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216415002091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3814845 + ... + 7548898.

It is an arithmetic number, because the mean of its divisors is an integer number (1364012919808).

Almost surely, 2^{21216415002061} is an apocalyptic number.

It is an amenable number.

21216415002061 is a deficient number, since it is larger than the sum of its proper divisors (607791714867).

21216415002061 is a wasteful number, since it uses less digits than its factorization.

21216415002061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11364172.

The product of its (nonzero) digits is 5760, while the sum is 31.

Adding to 21216415002061 its reverse (16020051461212), we get a palindrome (37236466463273).

The spelling of 21216415002061 in words is "twenty-one trillion, two hundred sixteen billion, four hundred fifteen million, two thousand, sixty-one".