21120645314645 has 32 divisors (see below), whose sum is σ = 26230723136640. Its totient is φ = 16315365830400.

The previous prime is 21120645314617. The next prime is 21120645314647. The reversal of 21120645314645 is 54641354602112.

It is a happy number.

It is not a de Polignac number, because 21120645314645 - 2⁶ = 21120645314581 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120645314596 and 21120645314605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120645314647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13572227 + ... + 15048143.

It is an arithmetic number, because the mean of its divisors is an integer number (819710098020).

Almost surely, 2^{21120645314645} is an apocalyptic number.

It is an amenable number.

21120645314645 is a deficient number, since it is larger than the sum of its proper divisors (5110077821995).

21120645314645 is a wasteful number, since it uses less digits than its factorization.

21120645314645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1476725.

The product of its (nonzero) digits is 691200, while the sum is 44.

Adding to 21120645314645 its reverse (54641354602112), we get a palindrome (75761999916757).

The spelling of 21120645314645 in words is "twenty-one trillion, one hundred twenty billion, six hundred forty-five million, three hundred fourteen thousand, six hundred forty-five".