640772653 has 8 divisors (see below), whose sum is σ = 678783672. Its totient is φ = 602797056.

The previous prime is 640772651. The next prime is 640772669. The reversal of 640772653 is 356277046.

It can be written as a sum of positive squares in 4 ways, for example, as 290259369 + 350513284 = 17037^2 + 18722^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640772653 - 2¹ = 640772651 is a prime.

It is a super-3 number, since 3×640772653³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640772651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34501 + ... + 49717.

It is an arithmetic number, because the mean of its divisors is an integer number (84847959).

Almost surely, 2^640772653 is an apocalyptic number.

It is an amenable number.

640772653 is a deficient number, since it is larger than the sum of its proper divisors (38011019).

640772653 is a wasteful number, since it uses less digits than its factorization.

640772653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17711.

The product of its (nonzero) digits is 211680, while the sum is 40.

The square root of 640772653 is about 25313.4875708583. The cubic root of 640772653 is about 862.1205345522.

The spelling of 640772653 in words is "six hundred forty million, seven hundred seventy-two thousand, six hundred fifty-three".