20677999 has 4 divisors (see below), whose sum is σ = 20809864. Its totient is φ = 20546136.

The previous prime is 20677997. The next prime is 20678027. The reversal of 20677999 is 99977602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99977602 = 2 ⋅49988801.

It is a cyclic number.

It is not a de Polignac number, because 20677999 - 2¹ = 20677997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20677991) 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, 65697 + ... + 66010.

It is an arithmetic number, because the mean of its divisors is an integer number (5202466).

Almost surely, 2^20677999 is an apocalyptic number.

20677999 is a deficient number, since it is larger than the sum of its proper divisors (131865).

20677999 is a wasteful number, since it uses less digits than its factorization.

20677999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131864.

The product of its (nonzero) digits is 428652, while the sum is 49.

The square root of 20677999 is about 4547.3067853401. The cubic root of 20677999 is about 274.4750271187.

The spelling of 20677999 in words is "twenty million, six hundred seventy-seven thousand, nine hundred ninety-nine".