20642051 has 4 divisors (see below), whose sum is σ = 20691504. Its totient is φ = 20592600.

The previous prime is 20642047. The next prime is 20642053. The reversal of 20642051 is 15024602.

It is a happy number.

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 20642051 - 2² = 20642047 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20642053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24095 + ... + 24936.

It is an arithmetic number, because the mean of its divisors is an integer number (5172876).

Almost surely, 2^20642051 is an apocalyptic number.

20642051 is a deficient number, since it is larger than the sum of its proper divisors (49453).

20642051 is an equidigital number, since it uses as much as digits as its factorization.

20642051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49452.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20642051 is about 4543.3523966340. The cubic root of 20642051 is about 274.3158796834.

Adding to 20642051 its reverse (15024602), we get a palindrome (35666653).

The spelling of 20642051 in words is "twenty million, six hundred forty-two thousand, fifty-one".