19977161 has 2 divisors, whose sum is σ = 19977162. Its totient is φ = 19977160.

The previous prime is 19977121. The next prime is 19977163. The reversal of 19977161 is 16177991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17480761 + 2496400 = 4181^2 + 1580^2 .

It is a cyclic number.

It is not a de Polignac number, because 19977161 - 2¹⁴ = 19960777 is a prime.

It is a Sophie Germain prime.

Together with 19977163, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19977163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9988580 + 9988581.

It is an arithmetic number, because the mean of its divisors is an integer number (9988581).

Almost surely, 2^19977161 is an apocalyptic number.

It is an amenable number.

19977161 is a deficient number, since it is larger than the sum of its proper divisors (1).

19977161 is an equidigital number, since it uses as much as digits as its factorization.

19977161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23814, while the sum is 41.

The square root of 19977161 is about 4469.5817477701. The cubic root of 19977161 is about 271.3383979975.

The spelling of 19977161 in words is "nineteen million, nine hundred seventy-seven thousand, one hundred sixty-one".