19513421 has 2 divisors, whose sum is σ = 19513422. Its totient is φ = 19513420.

The previous prime is 19513397. The next prime is 19513451. The reversal of 19513421 is 12431591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17757796 + 1755625 = 4214^2 + 1325^2 .

It is a cyclic number.

It is not a de Polignac number, because 19513421 - 2¹⁸ = 19251277 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 (19513451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9756710 + 9756711.

It is an arithmetic number, because the mean of its divisors is an integer number (9756711).

Almost surely, 2^19513421 is an apocalyptic number.

It is an amenable number.

19513421 is a deficient number, since it is larger than the sum of its proper divisors (1).

19513421 is an equidigital number, since it uses as much as digits as its factorization.

19513421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 26.

The square root of 19513421 is about 4417.3998007878. The cubic root of 19513421 is about 269.2223669529. Note that the first 3 decimals are identical.

The spelling of 19513421 in words is "nineteen million, five hundred thirteen thousand, four hundred twenty-one".