61171983857 has 4 divisors (see below), whose sum is σ = 62825280756. Its totient is φ = 59518686960.

The previous prime is 61171983841. The next prime is 61171983937. The reversal of 61171983857 is 75838917116.

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 26888128576 + 34283855281 = 163976^2 + 185159^2 .

It is a cyclic number.

It is not a de Polignac number, because 61171983857 - 2⁴ = 61171983841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61171982857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 826648394 + ... + 826648467.

It is an arithmetic number, because the mean of its divisors is an integer number (15706320189).

Almost surely, 2^61171983857 is an apocalyptic number.

It is an amenable number.

61171983857 is a deficient number, since it is larger than the sum of its proper divisors (1653296899).

61171983857 is a wasteful number, since it uses less digits than its factorization.

61171983857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1653296898.

The product of its digits is 2540160, while the sum is 56.

The spelling of 61171983857 in words is "sixty-one billion, one hundred seventy-one million, nine hundred eighty-three thousand, eight hundred fifty-seven".