19612121 has 2 divisors, whose sum is σ = 19612122. Its totient is φ = 19612120.

The previous prime is 19612069. The next prime is 19612157. The reversal of 19612121 is 12121691.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11833600 + 7778521 = 3440^2 + 2789^2 .

It is a cyclic number.

It is not a de Polignac number, because 19612121 - 2²² = 15417817 is a prime.

It is not a weakly prime, because it can be changed into another prime (19612421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9806060 + 9806061.

It is an arithmetic number, because the mean of its divisors is an integer number (9806061).

Almost surely, 2^19612121 is an apocalyptic number.

It is an amenable number.

19612121 is a deficient number, since it is larger than the sum of its proper divisors (1).

19612121 is an equidigital number, since it uses as much as digits as its factorization.

19612121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 23.

The square root of 19612121 is about 4428.5574400701. The cubic root of 19612121 is about 269.6755178342.

The spelling of 19612121 in words is "nineteen million, six hundred twelve thousand, one hundred twenty-one".