19421840 has 20 divisors (see below), whose sum is σ = 45155964. Its totient is φ = 7768704.

The previous prime is 19421833. The next prime is 19421849. The reversal of 19421840 is 4812491.

It can be written as a sum of positive squares in 2 ways, for example, as 10445824 + 8976016 = 3232^2 + 2996^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (19421849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121307 + ... + 121466.

Almost surely, 2^19421840 is an apocalyptic number.

19421840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19421840 is an abundant number, since it is smaller than the sum of its proper divisors (25734124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19421840 is a wasteful number, since it uses less digits than its factorization.

19421840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242786 (or 242780 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 19421840 is about 4407.0216700171. The cubic root of 19421840 is about 268.8005320520.

The spelling of 19421840 in words is "nineteen million, four hundred twenty-one thousand, eight hundred forty".