19999745 has 4 divisors (see below), whose sum is σ = 23999700. Its totient is φ = 15999792.

The previous prime is 19999739. The next prime is 19999789. The reversal of 19999745 is 54799991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7333264 + 12666481 = 2708^2 + 3559^2 .

It is a cyclic number.

It is not a de Polignac number, because 19999745 - 2⁴ = 19999729 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1999970 + ... + 1999979.

It is an arithmetic number, because the mean of its divisors is an integer number (5999925).

Almost surely, 2^19999745 is an apocalyptic number.

It is an amenable number.

19999745 is a deficient number, since it is larger than the sum of its proper divisors (3999955).

19999745 is an equidigital number, since it uses as much as digits as its factorization.

19999745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3999954.

The product of its digits is 918540, while the sum is 53.

The square root of 19999745 is about 4472.1074450420. The cubic root of 19999745 is about 271.4406080271.

The spelling of 19999745 in words is "nineteen million, nine hundred ninety-nine thousand, seven hundred forty-five".