19747421 has 8 divisors (see below), whose sum is σ = 21102840. Its totient is φ = 18413568.

The previous prime is 19747391. The next prime is 19747433. The reversal of 19747421 is 12474791.

It can be written as a sum of positive squares in 4 ways, for example, as 2524921 + 17222500 = 1589^2 + 4150^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19747421 - 2¹⁴ = 19731037 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19747451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3476 + ... + 7181.

It is an arithmetic number, because the mean of its divisors is an integer number (2637855).

Almost surely, 2^19747421 is an apocalyptic number.

It is an amenable number.

19747421 is a deficient number, since it is larger than the sum of its proper divisors (1355419).

19747421 is a wasteful number, since it uses less digits than its factorization.

19747421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10783.

The product of its digits is 14112, while the sum is 35.

The square root of 19747421 is about 4443.8070390151. The cubic root of 19747421 is about 270.2942425505.

The spelling of 19747421 in words is "nineteen million, seven hundred forty-seven thousand, four hundred twenty-one".