19679945 has 4 divisors (see below), whose sum is σ = 23615940. Its totient is φ = 15743952.

The previous prime is 19679941. The next prime is 19679963. The reversal of 19679945 is 54997691.

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 7268416 + 12411529 = 2696^2 + 3523^2 .

It is a cyclic number.

It is not a de Polignac number, because 19679945 - 2² = 19679941 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 19679893 and 19679902.

It is not an unprimeable number, because it can be changed into a prime (19679941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1967990 + ... + 1967999.

It is an arithmetic number, because the mean of its divisors is an integer number (5903985).

Almost surely, 2^19679945 is an apocalyptic number.

It is an amenable number.

19679945 is a deficient number, since it is larger than the sum of its proper divisors (3935995).

19679945 is an equidigital number, since it uses as much as digits as its factorization.

19679945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3935994.

The product of its digits is 612360, while the sum is 50.

The square root of 19679945 is about 4436.2084035807. The cubic root of 19679945 is about 269.9860303701.

The spelling of 19679945 in words is "nineteen million, six hundred seventy-nine thousand, nine hundred forty-five".