19661040 has 240 divisors, whose sum is σ = 77995008. Its totient is φ = 4345344.

The previous prime is 19661009. The next prime is 19661051. The reversal of 19661040 is 4016691.

19661040 is a `hidden beast` number, since 1 + 9 + 6 + 610 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a junction number, because it is equal to n+sod(n) for n = 19660995 and 19661013.

It is a congruent number.

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, 236839 + ... + 236921.

Almost surely, 2^19661040 is an apocalyptic number.

19661040 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 19661040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38997504).

19661040 is an abundant number, since it is smaller than the sum of its proper divisors (58333968).

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

19661040 is a wasteful number, since it uses less digits than its factorization.

19661040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 147 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 19661040 is about 4434.0771305876. The cubic root of 19661040 is about 269.8995511117.

The spelling of 19661040 in words is "nineteen million, six hundred sixty-one thousand, forty".