20643240245 has 8 divisors (see below), whose sum is σ = 24781123584. Its totient is φ = 16508435344.

The previous prime is 20643240203. The next prime is 20643240257. The reversal of 20643240245 is 54204234602.

It is a happy number.

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 20643240245 - 2¹² = 20643236149 is a prime.

It is a super-2 number, since 2×20643240245² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent 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, 754829 + ... + 781698.

It is an arithmetic number, because the mean of its divisors is an integer number (3097640448).

Almost surely, 2^20643240245 is an apocalyptic number.

It is an amenable number.

20643240245 is a deficient number, since it is larger than the sum of its proper divisors (4137883339).

20643240245 is a wasteful number, since it uses less digits than its factorization.

20643240245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1539219.

The product of its (nonzero) digits is 46080, while the sum is 32.

Adding to 20643240245 its reverse (54204234602), we get a palindrome (74847474847).

The spelling of 20643240245 in words is "twenty billion, six hundred forty-three million, two hundred forty thousand, two hundred forty-five".