640081294 has 4 divisors (see below), whose sum is σ = 960121944. Its totient is φ = 320040646.

The previous prime is 640081289. The next prime is 640081361. The reversal of 640081294 is 492180046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 492180046 = 2 ⋅246090023.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160020322 + ... + 160020325.

It is an arithmetic number, because the mean of its divisors is an integer number (240030486).

Almost surely, 2^640081294 is an apocalyptic number.

640081294 is a deficient number, since it is larger than the sum of its proper divisors (320040650).

640081294 is a wasteful number, since it uses less digits than its factorization.

640081294 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320040649.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 640081294 is about 25299.8279440790. The cubic root of 640081294 is about 861.8103625125.

The spelling of 640081294 in words is "six hundred forty million, eighty-one thousand, two hundred ninety-four".