21238642945 has 8 divisors (see below), whose sum is σ = 27446861736. Its totient is φ = 15683920896.

The previous prime is 21238642939. The next prime is 21238642961. The reversal of 21238642945 is 54924683212.

It can be written as a sum of positive squares in 4 ways, for example, as 764467201 + 20474175744 = 27649^2 + 143088^2 .

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 21238642945 - 2²¹ = 21236545793 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21238642895 and 21238642904.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163374112 + ... + 163374241.

It is an arithmetic number, because the mean of its divisors is an integer number (3430857717).

Almost surely, 2^21238642945 is an apocalyptic number.

It is an amenable number.

21238642945 is a deficient number, since it is larger than the sum of its proper divisors (6208218791).

21238642945 is a wasteful number, since it uses less digits than its factorization.

21238642945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326748371.

The product of its digits is 829440, while the sum is 46.

The spelling of 21238642945 in words is "twenty-one billion, two hundred thirty-eight million, six hundred forty-two thousand, nine hundred forty-five".