19905961 has 2 divisors, whose sum is σ = 19905962. Its totient is φ = 19905960.

The previous prime is 19905943. The next prime is 19905979. The reversal of 19905961 is 16950991.

It is a balanced prime because it is at equal distance from previous prime (19905943) and next prime (19905979).

It can be written as a sum of positive squares in only one way, i.e., 18974736 + 931225 = 4356^2 + 965^2 .

It is a cyclic number.

It is not a de Polignac number, because 19905961 - 2⁹ = 19905449 is a prime.

It is not a weakly prime, because it can be changed into another prime (19905911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9952980 + 9952981.

It is an arithmetic number, because the mean of its divisors is an integer number (9952981).

Almost surely, 2^19905961 is an apocalyptic number.

It is an amenable number.

19905961 is a deficient number, since it is larger than the sum of its proper divisors (1).

19905961 is an equidigital number, since it uses as much as digits as its factorization.

19905961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21870, while the sum is 40.

The square root of 19905961 is about 4461.6096870972. The cubic root of 19905961 is about 271.0156579235.

The spelling of 19905961 in words is "nineteen million, nine hundred five thousand, nine hundred sixty-one".