19656961 has 2 divisors, whose sum is σ = 19656962. Its totient is φ = 19656960.

The previous prime is 19656937. The next prime is 19656979. The reversal of 19656961 is 16965691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 1806336 = 4225^2 + 1344^2 .

It is an emirp because it is prime and its reverse (16965691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19656961 - 2²¹ = 17559809 is a prime.

It is a super-2 number, since 2×19656961² = 772792231511042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19656761) 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, 9828480 + 9828481.

It is an arithmetic number, because the mean of its divisors is an integer number (9828481).

Almost surely, 2^19656961 is an apocalyptic number.

It is an amenable number.

19656961 is a deficient number, since it is larger than the sum of its proper divisors (1).

19656961 is an equidigital number, since it uses as much as digits as its factorization.

19656961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87480, while the sum is 43.

The square root of 19656961 is about 4433.6171463039. The cubic root of 19656961 is about 269.8808848151.

The spelling of 19656961 in words is "nineteen million, six hundred fifty-six thousand, nine hundred sixty-one".