1616521649 has 2 divisors, whose sum is σ = 1616521650. Its totient is φ = 1616521648.

The previous prime is 1616521609. The next prime is 1616521667. The reversal of 1616521649 is 9461256161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 833361424 + 783160225 = 28868^2 + 27985^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1616521649 is a prime.

It is a super-2 number, since 2×1616521649² = 5226284483371358402, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1616521609) 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 as a sum of consecutive naturals, namely, 808260824 + 808260825.

It is an arithmetic number, because the mean of its divisors is an integer number (808260825).

Almost surely, 2^1616521649 is an apocalyptic number.

It is an amenable number.

1616521649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1616521649 is an equidigital number, since it uses as much as digits as its factorization.

1616521649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 41.

The square root of 1616521649 is about 40205.9902129024. The cubic root of 1616521649 is about 1173.6191169529.

The spelling of 1616521649 in words is "one billion, six hundred sixteen million, five hundred twenty-one thousand, six hundred forty-nine".