640145550 has 48 divisors (see below), whose sum is σ = 1731889152. Its totient is φ = 155186400.

The previous prime is 640145533. The next prime is 640145579. The reversal of 640145550 is 55541046.

640145550 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-5 number, since 5×640145550⁵ (a number of 45 digits) contains 55555 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 192334 + ... + 195633.

It is an arithmetic number, because the mean of its divisors is an integer number (36081024).

Almost surely, 2^640145550 is an apocalyptic number.

640145550 is an abundant number, since it is smaller than the sum of its proper divisors (1091743602).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640145550 is a wasteful number, since it uses less digits than its factorization.

640145550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387993 (or 387988 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 30.

The square root of 640145550 is about 25301.0978022694. The cubic root of 640145550 is about 861.8391998046.

Adding to 640145550 its reverse (55541046), we get a palindrome (695686596).

The spelling of 640145550 in words is "six hundred forty million, one hundred forty-five thousand, five hundred fifty".