19642840 has 96 divisors (see below), whose sum is σ = 52907040. Its totient is φ = 6428160.

The previous prime is 19642829. The next prime is 19642841. The reversal of 19642840 is 4824691.

It is a junction number, because it is equal to n+sod(n) for n = 19642796 and 19642805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19642841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 269044 + ... + 269116.

It is an arithmetic number, because the mean of its divisors is an integer number (551115).

Almost surely, 2^19642840 is an apocalyptic number.

19642840 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 19642840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26453520).

19642840 is an abundant number, since it is smaller than the sum of its proper divisors (33264200).

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

19642840 is a wasteful number, since it uses less digits than its factorization.

19642840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 19642840 is about 4432.0243681641. The cubic root of 19642840 is about 269.8162444246.

The spelling of 19642840 in words is "nineteen million, six hundred forty-two thousand, eight hundred forty".