1216857071 has 4 divisors (see below), whose sum is σ = 1280902200. Its totient is φ = 1152811944.

The previous prime is 1216857053. The next prime is 1216857091. The reversal of 1216857071 is 1707586121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1707586121 = 1973 ⋅865477.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216857071 is a prime.

It is a super-2 number, since 2×1216857071² = 2961482262485398082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216857091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32022536 + ... + 32022573.

It is an arithmetic number, because the mean of its divisors is an integer number (320225550).

Almost surely, 2^1216857071 is an apocalyptic number.

1216857071 is a deficient number, since it is larger than the sum of its proper divisors (64045129).

1216857071 is an equidigital number, since it uses as much as digits as its factorization.

1216857071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64045128.

The product of its (nonzero) digits is 23520, while the sum is 38.

The square root of 1216857071 is about 34883.4784819404. The cubic root of 1216857071 is about 1067.6113691997.

The spelling of 1216857071 in words is "one billion, two hundred sixteen million, eight hundred fifty-seven thousand, seventy-one".