19919745 has 24 divisors (see below), whose sum is σ = 34632000. Its totient is φ = 10591776.

The previous prime is 19919737. The next prime is 19919747. The reversal of 19919745 is 54791991.

It is not a de Polignac number, because 19919745 - 2³ = 19919737 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 19919745.

It is not an unprimeable number, because it can be changed into a prime (19919747) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26586 + ... + 27324.

It is an arithmetic number, because the mean of its divisors is an integer number (1443000).

Almost surely, 2^19919745 is an apocalyptic number.

19919745 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19919745 is a deficient number, since it is larger than the sum of its proper divisors (14712255).

19919745 is a wasteful number, since it uses less digits than its factorization.

19919745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1349 (or 1346 counting only the distinct ones).

The product of its digits is 102060, while the sum is 45.

The square root of 19919745 is about 4463.1541537348. The cubic root of 19919745 is about 271.0781989532.

The spelling of 19919745 in words is "nineteen million, nine hundred nineteen thousand, seven hundred forty-five".