21315554345 has 8 divisors (see below), whose sum is σ = 25634153160. Its totient is φ = 17015451520.

The previous prime is 21315554317. The next prime is 21315554347. The reversal of 21315554345 is 54345551312.

It can be written as a sum of positive squares in 4 ways, for example, as 6743201689 + 14572352656 = 82117^2 + 120716^2 .

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

It is not a de Polignac number, because 21315554345 - 2²⁶ = 21248445481 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21315554299 and 21315554308.

It is not an unprimeable number, because it can be changed into a prime (21315554347) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4621460 + ... + 4626069.

It is an arithmetic number, because the mean of its divisors is an integer number (3204269145).

Almost surely, 2^21315554345 is an apocalyptic number.

It is an amenable number.

21315554345 is a deficient number, since it is larger than the sum of its proper divisors (4318598815).

21315554345 is an equidigital number, since it uses as much as digits as its factorization.

21315554345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9247995.

The product of its digits is 180000, while the sum is 38.

The spelling of 21315554345 in words is "twenty-one billion, three hundred fifteen million, five hundred fifty-four thousand, three hundred forty-five".