19221840 has 160 divisors (see below), whose sum is σ = 72316800. Its totient is φ = 4654080.

The previous prime is 19221827. The next prime is 19221913. The reversal of 19221840 is 4812291.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23356 + ... + 24164.

It is an arithmetic number, because the mean of its divisors is an integer number (451980).

Almost surely, 2^19221840 is an apocalyptic number.

19221840 is a gapful number since it is divisible by the number (10) 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 19221840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36158400).

19221840 is an abundant number, since it is smaller than the sum of its proper divisors (53094960).

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

19221840 is a wasteful number, since it uses less digits than its factorization.

19221840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842 (or 830 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 19221840 is about 4384.2718893791. The cubic root of 19221840 is about 267.8746722242.

The spelling of 19221840 in words is "nineteen million, two hundred twenty-one thousand, eight hundred forty".