980621561 has 2 divisors, whose sum is σ = 980621562. Its totient is φ = 980621560.

The previous prime is 980621539. The next prime is 980621563. The reversal of 980621561 is 165126089.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 828345961 + 152275600 = 28781^2 + 12340^2 .

It is an emirp because it is prime and its reverse (165126089) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 980621561 - 2¹⁴ = 980605177 is a prime.

Together with 980621563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (980621563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490310780 + 490310781.

It is an arithmetic number, because the mean of its divisors is an integer number (490310781).

Almost surely, 2^980621561 is an apocalyptic number.

It is an amenable number.

980621561 is a deficient number, since it is larger than the sum of its proper divisors (1).

980621561 is an equidigital number, since it uses as much as digits as its factorization.

980621561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 980621561 is about 31314.8776302894. The cubic root of 980621561 is about 993.4983403672.

The spelling of 980621561 in words is "nine hundred eighty million, six hundred twenty-one thousand, five hundred sixty-one".