19669999 has 4 divisors (see below), whose sum is σ = 19992520. Its totient is φ = 19347480.

The previous prime is 19669987. The next prime is 19670011. The reversal of 19669999 is 99996691.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (19669987) and next prime (19670011).

It is a cyclic number.

It is not a de Polignac number, because 19669999 - 2⁵ = 19669967 is a prime.

It is a Duffinian number.

19669999 is a modest number, since divided by 9999 gives 1966 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19669399) 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, 161169 + ... + 161290.

It is an arithmetic number, because the mean of its divisors is an integer number (4998130).

Almost surely, 2^19669999 is an apocalyptic number.

19669999 is a deficient number, since it is larger than the sum of its proper divisors (322521).

19669999 is an equidigital number, since it uses as much as digits as its factorization.

19669999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322520.

The product of its digits is 2125764, while the sum is 58.

The square root of 19669999 is about 4435.0872595700. The cubic root of 19669999 is about 269.9405401759.

The spelling of 19669999 in words is "nineteen million, six hundred sixty-nine thousand, nine hundred ninety-nine".