19987426 has 4 divisors (see below), whose sum is σ = 29981142. Its totient is φ = 9993712.

The previous prime is 19987403. The next prime is 19987433. The reversal of 19987426 is 62478991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 62478991 = 1973 ⋅31667.

It can be written as a sum of positive squares in only one way, i.e., 17430625 + 2556801 = 4175^2 + 1599^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4996855 + ... + 4996858.

Almost surely, 2^19987426 is an apocalyptic number.

19987426 is a deficient number, since it is larger than the sum of its proper divisors (9993716).

19987426 is an equidigital number, since it uses as much as digits as its factorization.

19987426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9993715.

The product of its digits is 217728, while the sum is 46.

The square root of 19987426 is about 4470.7299180335. The cubic root of 19987426 is about 271.3848645889.

The spelling of 19987426 in words is "nineteen million, nine hundred eighty-seven thousand, four hundred twenty-six".