640020111 has 16 divisors (see below), whose sum is σ = 929251200. Its totient is φ = 390283488.

The previous prime is 640020109. The next prime is 640020211. The reversal of 640020111 is 111020046.

It is not a de Polignac number, because 640020111 - 2¹ = 640020109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640020211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191941 + ... + 195246.

It is an arithmetic number, because the mean of its divisors is an integer number (58078200).

Almost surely, 2^640020111 is an apocalyptic number.

640020111 is a deficient number, since it is larger than the sum of its proper divisors (289231089).

640020111 is a wasteful number, since it uses less digits than its factorization.

640020111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387238.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 640020111 is about 25298.6187567622. The cubic root of 640020111 is about 861.7829025507.

Adding to 640020111 its reverse (111020046), we get a palindrome (751040157).

The spelling of 640020111 in words is "six hundred forty million, twenty thousand, one hundred eleven".