640401663001 has 9 divisors (see below), whose sum is σ = 642504387391. Its totient is φ = 638305805632.

The previous prime is 640401662981. The next prime is 640401663019. The reversal of 640401663001 is 100366104046.

The square root of 640401663001 is 800251.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 260176505625 + 380225157376 = 510075^2 + 616624^2 .

It is not a de Polignac number, because 640401663001 - 2¹⁵ = 640401630233 is a prime.

It is a super-2 number, since 2×640401663001² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640401669001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 282487470 + ... + 282489736.

Almost surely, 2^640401663001 is an apocalyptic number.

640401663001 is the 800251-st square number.

640401663001 is the 400126-th centered octagonal number.

It is an amenable number.

640401663001 is a deficient number, since it is larger than the sum of its proper divisors (2102724390).

640401663001 is an frugal number, since it uses more digits than its factorization.

640401663001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5240 (or 2620 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 31.

Adding to 640401663001 its reverse (100366104046), we get a palindrome (740767767047).

The spelling of 640401663001 in words is "six hundred forty billion, four hundred one million, six hundred sixty-three thousand, one".