20616961 has 2 divisors, whose sum is σ = 20616962. Its totient is φ = 20616960.

The previous prime is 20616931. The next prime is 20616979. The reversal of 20616961 is 16961602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11943936 + 8673025 = 3456^2 + 2945^2 .

It is a cyclic number.

It is not a de Polignac number, because 20616961 - 2¹⁹ = 20092673 is a prime.

It is not a weakly prime, because it can be changed into another prime (20616931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10308480 + 10308481.

It is an arithmetic number, because the mean of its divisors is an integer number (10308481).

Almost surely, 2^20616961 is an apocalyptic number.

It is an amenable number.

20616961 is a deficient number, since it is larger than the sum of its proper divisors (1).

20616961 is an equidigital number, since it uses as much as digits as its factorization.

20616961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 20616961 is about 4540.5903801158. The cubic root of 20616961 is about 274.2046928016.

The spelling of 20616961 in words is "twenty million, six hundred sixteen thousand, nine hundred sixty-one".