1216511623 has 2 divisors, whose sum is σ = 1216511624. Its totient is φ = 1216511622.

The previous prime is 1216511591. The next prime is 1216511693. The reversal of 1216511623 is 3261156121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1216511623 - 2⁵ = 1216511591 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1216511591 and 1216511600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216511693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608255811 + 608255812.

It is an arithmetic number, because the mean of its divisors is an integer number (608255812).

Almost surely, 2^1216511623 is an apocalyptic number.

1216511623 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216511623 is an equidigital number, since it uses as much as digits as its factorization.

1216511623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 28.

The square root of 1216511623 is about 34878.5266747321. The cubic root of 1216511623 is about 1067.5103331986.

Adding to 1216511623 its reverse (3261156121), we get a palindrome (4477667744).

The spelling of 1216511623 in words is "one billion, two hundred sixteen million, five hundred eleven thousand, six hundred twenty-three".