1216621589 has 2 divisors, whose sum is σ = 1216621590. Its totient is φ = 1216621588.

The previous prime is 1216621583. The next prime is 1216621603. The reversal of 1216621589 is 9851266121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1085175364 + 131446225 = 32942^2 + 11465^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216621589 - 2⁴ = 1216621573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216621583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608310794 + 608310795.

It is an arithmetic number, because the mean of its divisors is an integer number (608310795).

Almost surely, 2^1216621589 is an apocalyptic number.

It is an amenable number.

1216621589 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216621589 is an equidigital number, since it uses as much as digits as its factorization.

1216621589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 41.

The square root of 1216621589 is about 34880.1030531735. The cubic root of 1216621589 is about 1067.5424979288.

The spelling of 1216621589 in words is "one billion, two hundred sixteen million, six hundred twenty-one thousand, five hundred eighty-nine".