19645961 has 2 divisors, whose sum is σ = 19645962. Its totient is φ = 19645960.

The previous prime is 19645907. The next prime is 19645991. The reversal of 19645961 is 16954691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 109561 = 4420^2 + 331^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19645961 is a prime.

It is a super-2 number, since 2×19645961² = 771927567227042, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19645991) 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, 9822980 + 9822981.

It is an arithmetic number, because the mean of its divisors is an integer number (9822981).

Almost surely, 2^19645961 is an apocalyptic number.

It is an amenable number.

19645961 is a deficient number, since it is larger than the sum of its proper divisors (1).

19645961 is an equidigital number, since it uses as much as digits as its factorization.

19645961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 41.

The square root of 19645961 is about 4432.3764506188. The cubic root of 19645961 is about 269.8305338027.

The spelling of 19645961 in words is "nineteen million, six hundred forty-five thousand, nine hundred sixty-one".