19939121 has 2 divisors, whose sum is σ = 19939122. Its totient is φ = 19939120.

The previous prime is 19939111. The next prime is 19939123. The reversal of 19939121 is 12193991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19360000 + 579121 = 4400^2 + 761^2 .

It is a cyclic number.

It is not a de Polignac number, because 19939121 - 2¹⁴ = 19922737 is a prime.

Together with 19939123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19939123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9969560 + 9969561.

It is an arithmetic number, because the mean of its divisors is an integer number (9969561).

Almost surely, 2^19939121 is an apocalyptic number.

It is an amenable number.

19939121 is a deficient number, since it is larger than the sum of its proper divisors (1).

19939121 is an equidigital number, since it uses as much as digits as its factorization.

19939121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374, while the sum is 35.

The square root of 19939121 is about 4465.3242883356. The cubic root of 19939121 is about 271.1660633492.

The spelling of 19939121 in words is "nineteen million, nine hundred thirty-nine thousand, one hundred twenty-one".