22191988 has 48 divisors (see below), whose sum is σ = 48996864. Its totient is φ = 8559360.

The previous prime is 22191979. The next prime is 22191991. The reversal of 22191988 is 88919122.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 22191988.

It is a congruent number.

It is an unprimeable number.

It is an upside-down number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14181 + ... + 15667.

It is an arithmetic number, because the mean of its divisors is an integer number (1020768).

Almost surely, 2^22191988 is an apocalyptic number.

22191988 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 22191988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24498432).

22191988 is an abundant number, since it is smaller than the sum of its proper divisors (26804876).

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

22191988 is a wasteful number, since it uses less digits than its factorization.

22191988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1552 (or 1550 counting only the distinct ones).

The product of its digits is 20736, while the sum is 40.

The square root of 22191988 is about 4710.8372928812. The cubic root of 22191988 is about 281.0166612462.

The spelling of 22191988 in words is "twenty-two million, one hundred ninety-one thousand, nine hundred eighty-eight".