19993408 has 14 divisors (see below), whose sum is σ = 39674546. Its totient is φ = 9996672.

The previous prime is 19993381. The next prime is 19993447. The reversal of 19993408 is 80439991.

It can be written as a sum of positive squares in only one way, i.e., 17707264 + 2286144 = 4208^2 + 1512^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156135 + ... + 156262.

Almost surely, 2^19993408 is an apocalyptic number.

It is an amenable number.

19993408 is a deficient number, since it is larger than the sum of its proper divisors (19681138).

19993408 is an equidigital number, since it uses as much as digits as its factorization.

19993408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312409 (or 312399 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 19993408 is about 4471.3988862547. The cubic root of 19993408 is about 271.4119359809.

The spelling of 19993408 in words is "nineteen million, nine hundred ninety-three thousand, four hundred eight".