19689640 has 32 divisors (see below), whose sum is σ = 44637480. Its totient is φ = 7816192.

The previous prime is 19689623. The next prime is 19689671. The reversal of 19689640 is 4698691.

It can be written as a sum of positive squares in 4 ways, for example, as 14945956 + 4743684 = 3866^2 + 2178^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3684 + ... + 7276.

Almost surely, 2^19689640 is an apocalyptic number.

19689640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19689640 is an abundant number, since it is smaller than the sum of its proper divisors (24947840).

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

19689640 is a wasteful number, since it uses less digits than its factorization.

19689640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3741 (or 3737 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 19689640 is about 4437.3009814526. The cubic root of 19689640 is about 270.0303578120.

The spelling of 19689640 in words is "nineteen million, six hundred eighty-nine thousand, six hundred forty".