19999949 has 4 divisors (see below), whose sum is σ = 20869536. Its totient is φ = 19130364.

The previous prime is 19999927. The next prime is 19999963. The reversal of 19999949 is 94999991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94999991 = 911 ⋅104281.

It is a cyclic number.

It is not a de Polignac number, because 19999949 - 2¹² = 19995853 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 434759 + ... + 434804.

It is an arithmetic number, because the mean of its divisors is an integer number (5217384).

Almost surely, 2^19999949 is an apocalyptic number.

It is an amenable number.

19999949 is a deficient number, since it is larger than the sum of its proper divisors (869587).

19999949 is an equidigital number, since it uses as much as digits as its factorization.

19999949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869586.

The product of its digits is 2125764, while the sum is 59.

The square root of 19999949 is about 4472.1302530226. The cubic root of 19999949 is about 271.4415309338.

The spelling of 19999949 in words is "nineteen million, nine hundred ninety-nine thousand, nine hundred forty-nine".