640938545 has 8 divisors (see below), whose sum is σ = 828289896. Its totient is φ = 473308416.

The previous prime is 640938523. The next prime is 640938553. The reversal of 640938545 is 545839046.

640938545 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3073009 + 637865536 = 1753^2 + 25256^2 .

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 640938545 - 2⁶ = 640938481 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640938496 and 640938505.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4930232 + ... + 4930361.

It is an arithmetic number, because the mean of its divisors is an integer number (103536237).

Almost surely, 2^640938545 is an apocalyptic number.

640938545 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

640938545 is a deficient number, since it is larger than the sum of its proper divisors (187351351).

640938545 is a wasteful number, since it uses less digits than its factorization.

640938545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9860611.

The product of its (nonzero) digits is 518400, while the sum is 44.

The square root of 640938545 is about 25316.7641099727. The cubic root of 640938545 is about 862.1949273229.

The spelling of 640938545 in words is "six hundred forty million, nine hundred thirty-eight thousand, five hundred forty-five".