20857011 has 32 divisors (see below), whose sum is σ = 34583040. Its totient is φ = 10907136.

The previous prime is 20857007. The next prime is 20857019. The reversal of 20857011 is 11075802.

It is not a de Polignac number, because 20857011 - 2² = 20857007 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20857019) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12420 + ... + 13998.

It is an arithmetic number, because the mean of its divisors is an integer number (1080720).

Almost surely, 2^20857011 is an apocalyptic number.

20857011 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20857011 is a deficient number, since it is larger than the sum of its proper divisors (13726029).

20857011 is a wasteful number, since it uses less digits than its factorization.

20857011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643.

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 20857011 is about 4566.9476677536. The cubic root of 20857011 is about 275.2648071849.

The spelling of 20857011 in words is "twenty million, eight hundred fifty-seven thousand, eleven".