19666040 has 16 divisors (see below), whose sum is σ = 44248680. Its totient is φ = 7866400.

The previous prime is 19666039. The next prime is 19666043. The reversal of 19666040 is 4066691.

It is a junction number, because it is equal to n+sod(n) for n = 19665988 and 19666006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19666043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245786 + ... + 245865.

Almost surely, 2^19666040 is an apocalyptic number.

19666040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19666040 is an abundant number, since it is smaller than the sum of its proper divisors (24582640).

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

19666040 is a wasteful number, since it uses less digits than its factorization.

19666040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491662 (or 491658 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 19666040 is about 4434.6409099272. The cubic root of 19666040 is about 269.9224285616.

The spelling of 19666040 in words is "nineteen million, six hundred sixty-six thousand, forty".