19161421 has 2 divisors, whose sum is σ = 19161422. Its totient is φ = 19161420.

The previous prime is 19161419. The next prime is 19161427. The reversal of 19161421 is 12416191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16402500 + 2758921 = 4050^2 + 1661^2 .

It is an emirp because it is prime and its reverse (12416191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19161421 - 2¹ = 19161419 is a prime.

Together with 19161419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19161427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9580710 + 9580711.

It is an arithmetic number, because the mean of its divisors is an integer number (9580711).

Almost surely, 2^19161421 is an apocalyptic number.

It is an amenable number.

19161421 is a deficient number, since it is larger than the sum of its proper divisors (1).

19161421 is an equidigital number, since it uses as much as digits as its factorization.

19161421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 25.

The square root of 19161421 is about 4377.3760405065. The cubic root of 19161421 is about 267.5937121805.

The spelling of 19161421 in words is "nineteen million, one hundred sixty-one thousand, four hundred twenty-one".