20668779 has 12 divisors (see below), whose sum is σ = 30074616. Its totient is φ = 13677792.

The previous prime is 20668777. The next prime is 20668799. The reversal of 20668779 is 97786602.

It is a happy number.

It is not a de Polignac number, because 20668779 - 2¹ = 20668777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20668771) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7149 + ... + 9614.

It is an arithmetic number, because the mean of its divisors is an integer number (2506218).

Almost surely, 2^20668779 is an apocalyptic number.

20668779 is a deficient number, since it is larger than the sum of its proper divisors (9405837).

20668779 is a wasteful number, since it uses less digits than its factorization.

20668779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16906 (or 16903 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 45.

The square root of 20668779 is about 4546.2928854177. The cubic root of 20668779 is about 274.4342263305.

The spelling of 20668779 in words is "twenty million, six hundred sixty-eight thousand, seven hundred seventy-nine".