19491228 has 36 divisors (see below), whose sum is σ = 49657608. Its totient is φ = 6445920.

The previous prime is 19491223. The next prime is 19491233. The reversal of 19491228 is 82219491.

It is an interprime number because it is at equal distance from previous prime (19491223) and next prime (19491233).

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 19491192 and 19491201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19491221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2650 + ... + 6782.

It is an arithmetic number, because the mean of its divisors is an integer number (1379378).

Almost surely, 2^19491228 is an apocalyptic number.

19491228 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

19491228 is an abundant number, since it is smaller than the sum of its proper divisors (30166380).

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

19491228 is a wasteful number, since it uses less digits than its factorization.

19491228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4274 (or 4269 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 19491228 is about 4414.8870880239. The cubic root of 19491228 is about 269.1202642594.

The spelling of 19491228 in words is "nineteen million, four hundred ninety-one thousand, two hundred twenty-eight".