19478640 has 80 divisors (see below), whose sum is σ = 60808608. Its totient is φ = 5157888.

The previous prime is 19478623. The next prime is 19478647. The reversal of 19478640 is 4687491.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19478647) 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, 66334 + ... + 66626.

Almost surely, 2^19478640 is an apocalyptic number.

19478640 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 19478640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30404304).

19478640 is an abundant number, since it is smaller than the sum of its proper divisors (41329968).

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

19478640 is a wasteful number, since it uses less digits than its factorization.

19478640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586 (or 580 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 19478640 is about 4413.4612267471. The cubic root of 19478640 is about 269.0623165604.

The spelling of 19478640 in words is "nineteen million, four hundred seventy-eight thousand, six hundred forty".