640981201 has 12 divisors (see below), whose sum is σ = 746486820. Its totient is φ = 548782080.

The previous prime is 640981183. The next prime is 640981219. The reversal of 640981201 is 102189046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640981183) and next prime (640981219).

It can be written as a sum of positive squares in 2 ways, for example, as 230310976 + 410670225 = 15176^2 + 20265^2 .

It is not a de Polignac number, because 640981201 - 2¹³ = 640973009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640981261) 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 11 ways as a sum of consecutive naturals, for example, 38481 + ... + 52561.

It is an arithmetic number, because the mean of its divisors is an integer number (62207235).

Almost surely, 2^640981201 is an apocalyptic number.

It is an amenable number.

640981201 is a deficient number, since it is larger than the sum of its proper divisors (105505619).

640981201 is a wasteful number, since it uses less digits than its factorization.

640981201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15024 (or 15017 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 640981201 is about 25317.6065416935. The cubic root of 640981201 is about 862.2140539466.

The spelling of 640981201 in words is "six hundred forty million, nine hundred eighty-one thousand, two hundred one".