20668738 has 4 divisors (see below), whose sum is σ = 31003110. Its totient is φ = 10334368.

The previous prime is 20668733. The next prime is 20668759. The reversal of 20668738 is 83786602.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 16916769 + 3751969 = 4113^2 + 1937^2 .

It is a super-3 number, since 3×20668738³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20668738.

It is not an unprimeable number, because it can be changed into a prime (20668733) 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 as a sum of consecutive naturals, namely, 5167183 + ... + 5167186.

Almost surely, 2^20668738 is an apocalyptic number.

20668738 is a deficient number, since it is larger than the sum of its proper divisors (10334372).

20668738 is a wasteful number, since it uses less digits than its factorization.

20668738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10334371.

The product of its (nonzero) digits is 96768, while the sum is 40.

The square root of 20668738 is about 4546.2883762472. The cubic root of 20668738 is about 274.4340448682.

The spelling of 20668738 in words is "twenty million, six hundred sixty-eight thousand, seven hundred thirty-eight".