19847940 has 144 divisors (see below), whose sum is σ = 66572352. Its totient is φ = 4402944.

The previous prime is 19847929. The next prime is 19847953. The reversal of 19847940 is 4974891.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 19847892 and 19847901.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 126342 + ... + 126498.

It is an arithmetic number, because the mean of its divisors is an integer number (462308).

Almost surely, 2^19847940 is an apocalyptic number.

19847940 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 19847940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33286176).

19847940 is an abundant number, since it is smaller than the sum of its proper divisors (46724412).

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

19847940 is a wasteful number, since it uses less digits than its factorization.

19847940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 19847940 is about 4455.1026924191. The cubic root of 19847940 is about 270.7520869248.

The spelling of 19847940 in words is "nineteen million, eight hundred forty-seven thousand, nine hundred forty".