20724808651 has 4 divisors (see below), whose sum is σ = 21625887312. Its totient is φ = 19823729992.

The previous prime is 20724808609. The next prime is 20724808669. The reversal of 20724808651 is 15680842702.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-20724808651 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20724808598 and 20724808607.

It is not an unprimeable number, because it can be changed into a prime (20724808051) 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, 450539296 + ... + 450539341.

It is an arithmetic number, because the mean of its divisors is an integer number (5406471828).

Almost surely, 2^20724808651 is an apocalyptic number.

20724808651 is a deficient number, since it is larger than the sum of its proper divisors (901078661).

20724808651 is an equidigital number, since it uses as much as digits as its factorization.

20724808651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901078660.

The product of its (nonzero) digits is 215040, while the sum is 43.

The spelling of 20724808651 in words is "twenty billion, seven hundred twenty-four million, eight hundred eight thousand, six hundred fifty-one".