1216797857 has 4 divisors (see below), whose sum is σ = 1327415856. Its totient is φ = 1106179860.

The previous prime is 1216797839. The next prime is 1216797871. The reversal of 1216797857 is 7587976121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1216797857 - 2¹² = 1216793761 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1216797799 and 1216797808.

It is not an unprimeable number, because it can be changed into a prime (1216797817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55308983 + ... + 55309004.

It is an arithmetic number, because the mean of its divisors is an integer number (331853964).

Almost surely, 2^1216797857 is an apocalyptic number.

It is an amenable number.

1216797857 is a deficient number, since it is larger than the sum of its proper divisors (110617999).

1216797857 is a wasteful number, since it uses less digits than its factorization.

1216797857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110617998.

The product of its digits is 1481760, while the sum is 53.

The square root of 1216797857 is about 34882.6297317160. The cubic root of 1216797857 is about 1067.5940517550.

The spelling of 1216797857 in words is "one billion, two hundred sixteen million, seven hundred ninety-seven thousand, eight hundred fifty-seven".