20878725217 has 16 divisors (see below), whose sum is σ = 24484464000. Its totient is φ = 17796019920.

The previous prime is 20878725199. The next prime is 20878725221. The reversal of 20878725217 is 71252787802.

It is a happy number.

It is not a de Polignac number, because 20878725217 - 2⁷ = 20878725089 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20878720217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108634 + ... + 231427.

It is an arithmetic number, because the mean of its divisors is an integer number (1530279000).

Almost surely, 2^20878725217 is an apocalyptic number.

It is an amenable number.

20878725217 is a deficient number, since it is larger than the sum of its proper divisors (3605738783).

20878725217 is an equidigital number, since it uses as much as digits as its factorization.

20878725217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340261 (or 340247 counting only the distinct ones).

The product of its (nonzero) digits is 878080, while the sum is 49.

The spelling of 20878725217 in words is "twenty billion, eight hundred seventy-eight million, seven hundred twenty-five thousand, two hundred seventeen".