215671610557 has 4 divisors (see below), whose sum is σ = 232261734460. Its totient is φ = 199081486656.

The previous prime is 215671610549. The next prime is 215671610569. The reversal of 215671610557 is 755016176512.

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 143024650596 + 72646959961 = 378186^2 + 269531^2 .

It is not a de Polignac number, because 215671610557 - 2³ = 215671610549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215678610557) 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, 8295061932 + ... + 8295061957.

It is an arithmetic number, because the mean of its divisors is an integer number (58065433615).

Almost surely, 2^215671610557 is an apocalyptic number.

It is an amenable number.

215671610557 is a deficient number, since it is larger than the sum of its proper divisors (16590123903).

215671610557 is a wasteful number, since it uses less digits than its factorization.

215671610557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16590123902.

The product of its (nonzero) digits is 441000, while the sum is 46.

The spelling of 215671610557 in words is "two hundred fifteen billion, six hundred seventy-one million, six hundred ten thousand, five hundred fifty-seven".