19890688 has 40 divisors (see below), whose sum is σ = 40547628. Its totient is φ = 9744384.

The previous prime is 19890683. The next prime is 19890691. The reversal of 19890688 is 88609891.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16386304 + 3504384 = 4048^2 + 1872^2 .

It is a super-2 number, since 2×19890688² = 791278938226688, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19890683) 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, 26770 + ... + 27502.

Almost surely, 2^19890688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19890688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20273814).

19890688 is an abundant number, since it is smaller than the sum of its proper divisors (20656940).

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

19890688 is an frugal number, since it uses more digits than its factorization.

19890688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804 (or 788 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 49.

The square root of 19890688 is about 4459.8977566756. The cubic root of 19890688 is about 270.9463272472.

The spelling of 19890688 in words is "nineteen million, eight hundred ninety thousand, six hundred eighty-eight".