1216205131 has 2 divisors, whose sum is σ = 1216205132. Its totient is φ = 1216205130.

The previous prime is 1216205117. The next prime is 1216205141. The reversal of 1216205131 is 1315026121.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1315026121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1216205131 - 2¹³ = 1216196939 is a prime.

It is a super-2 number, since 2×1216205131² = 2958309841341454322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1216205141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608102565 + 608102566.

It is an arithmetic number, because the mean of its divisors is an integer number (608102566).

Almost surely, 2^1216205131 is an apocalyptic number.

1216205131 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216205131 is an equidigital number, since it uses as much as digits as its factorization.

1216205131 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 1216205131 is about 34874.1326917244. The cubic root of 1216205131 is about 1067.4206749627.

The spelling of 1216205131 in words is "one billion, two hundred sixteen million, two hundred five thousand, one hundred thirty-one".