19999917 has 12 divisors (see below), whose sum is σ = 33015840. Its totient is φ = 11428488.

The previous prime is 19999909. The next prime is 19999927. The reversal of 19999917 is 71999991.

It is not a de Polignac number, because 19999917 - 2³ = 19999909 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999927) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 158667 + ... + 158792.

It is an arithmetic number, because the mean of its divisors is an integer number (2751320).

Almost surely, 2^19999917 is an apocalyptic number.

It is an amenable number.

19999917 is a deficient number, since it is larger than the sum of its proper divisors (13015923).

19999917 is a wasteful number, since it uses less digits than its factorization.

19999917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317472 (or 317469 counting only the distinct ones).

The product of its digits is 413343, while the sum is 54.

The square root of 19999917 is about 4472.1266753078. The cubic root of 19999917 is about 271.4413861645.

The spelling of 19999917 in words is "nineteen million, nine hundred ninety-nine thousand, nine hundred seventeen".