20678511 has 16 divisors (see below), whose sum is σ = 33364224. Its totient is φ = 11121024.

The previous prime is 20678453. The next prime is 20678513. The reversal of 20678511 is 11587602.

It is not a de Polignac number, because 20678511 - 2⁶ = 20678447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20678513) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28605 + ... + 29318.

It is an arithmetic number, because the mean of its divisors is an integer number (2085264).

Almost surely, 2^20678511 is an apocalyptic number.

20678511 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20678511 is a deficient number, since it is larger than the sum of its proper divisors (12685713).

20678511 is a wasteful number, since it uses less digits than its factorization.

20678511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57950.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 20678511 is about 4547.3630820510. The cubic root of 20678511 is about 274.4772924902.

Subtracting from 20678511 its reverse (11587602), we obtain a palindrome (9090909).

The spelling of 20678511 in words is "twenty million, six hundred seventy-eight thousand, five hundred eleven".