19121421 has 16 divisors (see below), whose sum is σ = 28093248. Its totient is φ = 11472000.

The previous prime is 19121419. The next prime is 19121423. The reversal of 19121421 is 12412191.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (19121419) and next prime (19121423).

It is not a de Polignac number, because 19121421 - 2¹ = 19121419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19121423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 465 + ... + 6201.

It is an arithmetic number, because the mean of its divisors is an integer number (1755828).

Almost surely, 2^19121421 is an apocalyptic number.

19121421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19121421 is a deficient number, since it is larger than the sum of its proper divisors (8971827).

19121421 is a wasteful number, since it uses less digits than its factorization.

19121421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5852.

The product of its digits is 144, while the sum is 21.

The square root of 19121421 is about 4372.8047063641. The cubic root of 19121421 is about 267.4073793530.

It can be divided in two parts, 1912 and 1421, that added together give a palindrome (3333).

The spelling of 19121421 in words is "nineteen million, one hundred twenty-one thousand, four hundred twenty-one".