19942661 has 2 divisors, whose sum is σ = 19942662. Its totient is φ = 19942660.

The previous prime is 19942621. The next prime is 19942673. The reversal of 19942661 is 16624991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 1366561 = 4310^2 + 1169^2 .

It is a cyclic number.

It is not a de Polignac number, because 19942661 - 2⁶ = 19942597 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19942621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9971330 + 9971331.

It is an arithmetic number, because the mean of its divisors is an integer number (9971331).

Almost surely, 2^19942661 is an apocalyptic number.

It is an amenable number.

19942661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19942661 is an equidigital number, since it uses as much as digits as its factorization.

19942661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 38.

The square root of 19942661 is about 4465.7206585276. The cubic root of 19942661 is about 271.1821100456.

The spelling of 19942661 in words is "nineteen million, nine hundred forty-two thousand, six hundred sixty-one".