20668019 has 4 divisors (see below), whose sum is σ = 20712744. Its totient is φ = 20623296.

The previous prime is 20667973. The next prime is 20668027. The reversal of 20668019 is 91086602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91086602 = 2 ⋅45543301.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20668019 is a prime.

It is a super-2 number, since 2×20668019² = 854334018768722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20668069) 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, 21662 + ... + 22595.

It is an arithmetic number, because the mean of its divisors is an integer number (5178186).

Almost surely, 2^20668019 is an apocalyptic number.

20668019 is a deficient number, since it is larger than the sum of its proper divisors (44725).

20668019 is an equidigital number, since it uses as much as digits as its factorization.

20668019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44724.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 20668019 is about 4546.2093000653. The cubic root of 20668019 is about 274.4308626006.

The spelling of 20668019 in words is "twenty million, six hundred sixty-eight thousand, nineteen".