216870572557 has 4 divisors (see below), whose sum is σ = 217642354236. Its totient is φ = 216098790880.

The previous prime is 216870572537. The next prime is 216870572587. The reversal of 216870572557 is 755275078612.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 157308217641 + 59562354916 = 396621^2 + 244054^2 .

It is a cyclic number.

It is not a de Polignac number, because 216870572557 - 2²³ = 216862183949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216870572498 and 216870572507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216870572537) 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, 385890418 + ... + 385890979.

It is an arithmetic number, because the mean of its divisors is an integer number (54410588559).

Almost surely, 2^216870572557 is an apocalyptic number.

It is an amenable number.

216870572557 is a deficient number, since it is larger than the sum of its proper divisors (771781679).

216870572557 is an equidigital number, since it uses as much as digits as its factorization.

216870572557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771781678.

The product of its (nonzero) digits is 8232000, while the sum is 55.

The spelling of 216870572557 in words is "two hundred sixteen billion, eight hundred seventy million, five hundred seventy-two thousand, five hundred fifty-seven".