1216559431 has 4 divisors (see below), whose sum is σ = 1217938072. Its totient is φ = 1215180792.

The previous prime is 1216559317. The next prime is 1216559437. The reversal of 1216559431 is 1349556121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1349556121 = 6361 ⋅212161.

It is a cyclic number.

It is not a de Polignac number, because 1216559431 - 2²³ = 1208170823 is a prime.

It is a super-2 number, since 2×1216559431² = 2960033698310087522, 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 (1216559437) 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, 687996 + ... + 689761.

It is an arithmetic number, because the mean of its divisors is an integer number (304484518).

Almost surely, 2^1216559431 is an apocalyptic number.

1216559431 is a deficient number, since it is larger than the sum of its proper divisors (1378641).

1216559431 is an equidigital number, since it uses as much as digits as its factorization.

1216559431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378640.

The product of its digits is 32400, while the sum is 37.

The square root of 1216559431 is about 34879.2120180488. The cubic root of 1216559431 is about 1067.5243171355.

The spelling of 1216559431 in words is "one billion, two hundred sixteen million, five hundred fifty-nine thousand, four hundred thirty-one".