20215851 has 8 divisors (see below), whose sum is σ = 27116544. Its totient is φ = 13396200.

The previous prime is 20215849. The next prime is 20215861. The reversal of 20215851 is 15851202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20215851 - 2¹ = 20215849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20215841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19675 + ... + 20676.

It is an arithmetic number, because the mean of its divisors is an integer number (3389568).

Almost surely, 2^20215851 is an apocalyptic number.

20215851 is a deficient number, since it is larger than the sum of its proper divisors (6900693).

20215851 is a wasteful number, since it uses less digits than its factorization.

20215851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40521.

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 20215851 is about 4496.2040656536. The cubic root of 20215851 is about 272.4147858009.

The spelling of 20215851 in words is "twenty million, two hundred fifteen thousand, eight hundred fifty-one".