21513214945 has 8 divisors (see below), whose sum is σ = 25817084136. Its totient is φ = 17209754496.

The previous prime is 21513214897. The next prime is 21513214967. The reversal of 21513214945 is 54941231512.

It can be written as a sum of positive squares in 4 ways, for example, as 7674986449 + 13838228496 = 87607^2 + 117636^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21513214945 - 2⁷ = 21513214817 is a prime.

It is a Duffinian number.

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, 28899 + ... + 209431.

It is an arithmetic number, because the mean of its divisors is an integer number (3227135517).

Almost surely, 2^21513214945 is an apocalyptic number.

It is an amenable number.

21513214945 is a deficient number, since it is larger than the sum of its proper divisors (4303869191).

21513214945 is a wasteful number, since it uses less digits than its factorization.

21513214945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204371.

The product of its digits is 43200, while the sum is 37.

The spelling of 21513214945 in words is "twenty-one billion, five hundred thirteen million, two hundred fourteen thousand, nine hundred forty-five".