19649638 has 4 divisors (see below), whose sum is σ = 29474460. Its totient is φ = 9824818.

The previous prime is 19649621. The next prime is 19649639. The reversal of 19649638 is 83694691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83694691 = 229 ⋅365479.

It is a super-2 number, since 2×19649638² = 772216547062088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19649639) 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 as a sum of consecutive naturals, namely, 4912408 + ... + 4912411.

It is an arithmetic number, because the mean of its divisors is an integer number (7368615).

Almost surely, 2^19649638 is an apocalyptic number.

19649638 is a deficient number, since it is larger than the sum of its proper divisors (9824822).

19649638 is an equidigital number, since it uses as much as digits as its factorization.

19649638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9824821.

The product of its digits is 279936, while the sum is 46.

The square root of 19649638 is about 4432.7912199877. The cubic root of 19649638 is about 269.8473668637.

The spelling of 19649638 in words is "nineteen million, six hundred forty-nine thousand, six hundred thirty-eight".