19858642 has 4 divisors (see below), whose sum is σ = 29787966. Its totient is φ = 9929320.

The previous prime is 19858613. The next prime is 19858681. The reversal of 19858642 is 24685891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24685891 = 2179 ⋅11329.

It can be written as a sum of positive squares in only one way, i.e., 19722481 + 136161 = 4441^2 + 369^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4964659 + ... + 4964662.

Almost surely, 2^19858642 is an apocalyptic number.

19858642 is a deficient number, since it is larger than the sum of its proper divisors (9929324).

19858642 is an equidigital number, since it uses as much as digits as its factorization.

19858642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9929323.

The product of its digits is 138240, while the sum is 43.

The square root of 19858642 is about 4456.3036252033. The cubic root of 19858642 is about 270.8007413141.

The spelling of 19858642 in words is "nineteen million, eight hundred fifty-eight thousand, six hundred forty-two".