19887390 has 64 divisors (see below), whose sum is σ = 53812800. Its totient is φ = 5225472.

The previous prime is 19887379. The next prime is 19887391. The reversal of 19887390 is 9378891.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19887391) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19206 + ... + 20214.

It is an arithmetic number, because the mean of its divisors is an integer number (840825).

Almost surely, 2^19887390 is an apocalyptic number.

19887390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 19887390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26906400).

19887390 is an abundant number, since it is smaller than the sum of its proper divisors (33925410).

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

19887390 is a wasteful number, since it uses less digits than its factorization.

19887390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1098 (or 1092 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 19887390 is about 4459.5280019302. The cubic root of 19887390 is about 270.9313515565.

The spelling of 19887390 in words is "nineteen million, eight hundred eighty-seven thousand, three hundred ninety".