19669961 has 4 divisors (see below), whose sum is σ = 19680900. Its totient is φ = 19659024.

The previous prime is 19669957. The next prime is 19669967. The reversal of 19669961 is 16996691.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4020025 + 15649936 = 2005^2 + 3956^2 .

It is a cyclic number.

It is not a de Polignac number, because 19669961 - 2² = 19669957 is a prime.

19669961 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19669967) 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, 2066 + ... + 6603.

It is an arithmetic number, because the mean of its divisors is an integer number (4920225).

Almost surely, 2^19669961 is an apocalyptic number.

It is an amenable number.

19669961 is a deficient number, since it is larger than the sum of its proper divisors (10939).

19669961 is an equidigital number, since it uses as much as digits as its factorization.

19669961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10938.

The product of its digits is 157464, while the sum is 47.

The square root of 19669961 is about 4435.0829755485. The cubic root of 19669961 is about 269.9403663453.

The spelling of 19669961 in words is "nineteen million, six hundred sixty-nine thousand, nine hundred sixty-one".