20191388 has 48 divisors (see below), whose sum is σ = 42040320. Its totient is φ = 8306496.

The previous prime is 20191387. The next prime is 20191403. The reversal of 20191388 is 88319102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20191387) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88058 + ... + 88286.

It is an arithmetic number, because the mean of its divisors is an integer number (875840).

Almost surely, 2^20191388 is an apocalyptic number.

20191388 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20191388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21020160).

20191388 is an abundant number, since it is smaller than the sum of its proper divisors (21848932).

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

20191388 is a wasteful number, since it uses less digits than its factorization.

20191388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354 (or 352 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 20191388 is about 4493.4828362863. The cubic root of 20191388 is about 272.3048593087.

The spelling of 20191388 in words is "twenty million, one hundred ninety-one thousand, three hundred eighty-eight".