20647408253 has 4 divisors (see below), whose sum is σ = 20784146208. Its totient is φ = 20510670300.

The previous prime is 20647408241. The next prime is 20647408261. The reversal of 20647408253 is 35280474602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20647408253 - 2¹⁰ = 20647407229 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20647408253.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20647408153) 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, 68368751 + ... + 68369052.

It is an arithmetic number, because the mean of its divisors is an integer number (5196036552).

Almost surely, 2^20647408253 is an apocalyptic number.

It is an amenable number.

20647408253 is a deficient number, since it is larger than the sum of its proper divisors (136737955).

20647408253 is a wasteful number, since it uses less digits than its factorization.

20647408253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136737954.

The product of its (nonzero) digits is 322560, while the sum is 41.

The spelling of 20647408253 in words is "twenty billion, six hundred forty-seven million, four hundred eight thousand, two hundred fifty-three".