21216211615545 has 8 divisors (see below), whose sum is σ = 33945938584896. Its totient is φ = 11315312861616.

The previous prime is 21216211615493. The next prime is 21216211615559. The reversal of 21216211615545 is 54551611261212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21216211615545 - 2⁹ = 21216211615033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21216211615497 and 21216211615506.

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, 707207053837 + ... + 707207053866.

It is an arithmetic number, because the mean of its divisors is an integer number (4243242323112).

Almost surely, 2^{21216211615545} is an apocalyptic number.

It is an amenable number.

21216211615545 is a deficient number, since it is larger than the sum of its proper divisors (12729726969351).

21216211615545 is a wasteful number, since it uses less digits than its factorization.

21216211615545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1414414107711.

The product of its digits is 144000, while the sum is 42.

Adding to 21216211615545 its reverse (54551611261212), we get a palindrome (75767822876757).

The spelling of 21216211615545 in words is "twenty-one trillion, two hundred sixteen billion, two hundred eleven million, six hundred fifteen thousand, five hundred forty-five".