20100851 has 4 divisors (see below), whose sum is σ = 21283272. Its totient is φ = 18918432.

The previous prime is 20100811. The next prime is 20100853. The reversal of 20100851 is 15800102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20100851 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1182403 = 20100851 / (2 + 0 + 1 + 0 + 0 + 8 + 5 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20100853) 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, 591185 + ... + 591218.

It is an arithmetic number, because the mean of its divisors is an integer number (5320818).

Almost surely, 2^20100851 is an apocalyptic number.

20100851 is a deficient number, since it is larger than the sum of its proper divisors (1182421).

20100851 is a wasteful number, since it uses less digits than its factorization.

20100851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182420.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 20100851 is about 4483.3972610064. The cubic root of 20100851 is about 271.8972497931.

Adding to 20100851 its reverse (15800102), we get a palindrome (35900953).

The spelling of 20100851 in words is "twenty million, one hundred thousand, eight hundred fifty-one".