20145851 has 4 divisors (see below), whose sum is σ = 21977304. Its totient is φ = 18314400.

The previous prime is 20145847. The next prime is 20145857. The reversal of 20145851 is 15854102.

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

It is a cyclic number.

It is not a de Polignac number, because 20145851 - 2² = 20145847 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 20145851.

It is not an unprimeable number, because it can be changed into a prime (20145857) 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, 915710 + ... + 915731.

It is an arithmetic number, because the mean of its divisors is an integer number (5494326).

Almost surely, 2^20145851 is an apocalyptic number.

20145851 is a deficient number, since it is larger than the sum of its proper divisors (1831453).

20145851 is a wasteful number, since it uses less digits than its factorization.

20145851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1831452.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 20145851 is about 4488.4129711959. The cubic root of 20145851 is about 272.0999983747.

Adding to 20145851 its reverse (15854102), we get a palindrome (35999953).

The spelling of 20145851 in words is "twenty million, one hundred forty-five thousand, eight hundred fifty-one".