640461243 has 16 divisors (see below), whose sum is σ = 891830016. Its totient is φ = 408064800.

The previous prime is 640461203. The next prime is 640461277. The reversal of 640461243 is 342164046.

It is not a de Polignac number, because 640461243 - 2⁹ = 640460731 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640461243.

It is not an unprimeable number, because it can be changed into a prime (640461203) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96921 + ... + 103317.

It is an arithmetic number, because the mean of its divisors is an integer number (55739376).

Almost surely, 2^640461243 is an apocalyptic number.

640461243 is a deficient number, since it is larger than the sum of its proper divisors (251368773).

640461243 is a wasteful number, since it uses less digits than its factorization.

640461243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7874.

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 640461243 is about 25307.3357546779. The cubic root of 640461243 is about 861.9808508656.

The spelling of 640461243 in words is "six hundred forty million, four hundred sixty-one thousand, two hundred forty-three".