19695661 has 2 divisors, whose sum is σ = 19695662. Its totient is φ = 19695660.

The previous prime is 19695653. The next prime is 19695667. The reversal of 19695661 is 16659691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19527561 + 168100 = 4419^2 + 410^2 .

It is a cyclic number.

It is not a de Polignac number, because 19695661 - 2³ = 19695653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19695667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9847830 + 9847831.

It is an arithmetic number, because the mean of its divisors is an integer number (9847831).

Almost surely, 2^19695661 is an apocalyptic number.

It is an amenable number.

19695661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19695661 is an equidigital number, since it uses as much as digits as its factorization.

19695661 is an evil number, because the sum of its binary digits is even.

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

The square root of 19695661 is about 4437.9793825569. The cubic root of 19695661 is about 270.0578796811.

The spelling of 19695661 in words is "nineteen million, six hundred ninety-five thousand, six hundred sixty-one".