19864961 has 2 divisors, whose sum is σ = 19864962. Its totient is φ = 19864960.

The previous prime is 19864919. The next prime is 19864981. The reversal of 19864961 is 16946891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19855936 + 9025 = 4456^2 + 95^2 .

It is a cyclic number.

It is not a de Polignac number, because 19864961 - 2¹⁰ = 19863937 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19864981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9932480 + 9932481.

It is an arithmetic number, because the mean of its divisors is an integer number (9932481).

Almost surely, 2^19864961 is an apocalyptic number.

It is an amenable number.

19864961 is a deficient number, since it is larger than the sum of its proper divisors (1).

19864961 is an equidigital number, since it uses as much as digits as its factorization.

19864961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 44.

The square root of 19864961 is about 4457.0125644876. The cubic root of 19864961 is about 270.8294611097.

The spelling of 19864961 in words is "nineteen million, eight hundred sixty-four thousand, nine hundred sixty-one".