21903033217 has 4 divisors (see below), whose sum is σ = 23587881940. Its totient is φ = 20218184496.

The previous prime is 21903033211. The next prime is 21903033241. The reversal of 21903033217 is 71233030912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8185001841 + 13718031376 = 90471^2 + 117124^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21903033217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21903033211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842424342 + ... + 842424367.

It is an arithmetic number, because the mean of its divisors is an integer number (5896970485).

Almost surely, 2^21903033217 is an apocalyptic number.

It is an amenable number.

21903033217 is a deficient number, since it is larger than the sum of its proper divisors (1684848723).

21903033217 is a wasteful number, since it uses less digits than its factorization.

21903033217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1684848722.

The product of its (nonzero) digits is 6804, while the sum is 31.

The spelling of 21903033217 in words is "twenty-one billion, nine hundred three million, thirty-three thousand, two hundred seventeen".