20509143849 has 12 divisors (see below), whose sum is σ = 29627522496. Its totient is φ = 13671283992.

The previous prime is 20509143839. The next prime is 20509143857. The reversal of 20509143849 is 94834190502.

20509143849 is a `hidden beast` number, since 20 + 509 + 1 + 43 + 84 + 9 = 666.

It is not a de Polignac number, because 20509143849 - 2⁵ = 20509143817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20509143829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31797 + ... + 205010.

It is an arithmetic number, because the mean of its divisors is an integer number (2468960208).

Almost surely, 2^20509143849 is an apocalyptic number.

It is an amenable number.

20509143849 is a deficient number, since it is larger than the sum of its proper divisors (9118378647).

20509143849 is a wasteful number, since it uses less digits than its factorization.

20509143849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246436 (or 246433 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 20509143849 in words is "twenty billion, five hundred nine million, one hundred forty-three thousand, eight hundred forty-nine".