21213610645451 has 40 divisors (see below), whose sum is σ = 25708781937024. Its totient is φ = 17484453866880.

The previous prime is 21213610645397. The next prime is 21213610645489. The reversal of 21213610645451 is 15454601631212.

It is not a de Polignac number, because 21213610645451 - 2¹⁰ = 21213610644427 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21213610645399 and 21213610645408.

It is not an unprimeable number, because it can be changed into a prime (21213610641451) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 10777991 + ... + 12593343.

Almost surely, 2^{21213610645451} is an apocalyptic number.

21213610645451 is a deficient number, since it is larger than the sum of its proper divisors (4495171291573).

21213610645451 is an equidigital number, since it uses as much as digits as its factorization.

21213610645451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1815569 (or 1815548 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 41.

The spelling of 21213610645451 in words is "twenty-one trillion, two hundred thirteen billion, six hundred ten million, six hundred forty-five thousand, four hundred fifty-one".