19397640 has 64 divisors (see below), whose sum is σ = 58766400. Its totient is φ = 5121792.

The previous prime is 19397617. The next prime is 19397683. The reversal of 19397640 is 4679391.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12339 + ... + 13821.

It is an arithmetic number, because the mean of its divisors is an integer number (918225).

Almost surely, 2^19397640 is an apocalyptic number.

19397640 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 19397640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29383200).

19397640 is an abundant number, since it is smaller than the sum of its proper divisors (39368760).

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

19397640 is a wasteful number, since it uses less digits than its factorization.

19397640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1606 (or 1602 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 39.

The square root of 19397640 is about 4404.2751957615. The cubic root of 19397640 is about 268.6888420419.

The spelling of 19397640 in words is "nineteen million, three hundred ninety-seven thousand, six hundred forty".