640693494 has 24 divisors (see below), whose sum is σ = 1586479440. Its totient is φ = 183055248.

The previous prime is 640693489. The next prime is 640693499. The reversal of 640693494 is 494396046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640693489) and next prime (640693499).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640693499) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2542309 + ... + 2542560.

It is an arithmetic number, because the mean of its divisors is an integer number (66103310).

Almost surely, 2^640693494 is an apocalyptic number.

640693494 is an abundant number, since it is smaller than the sum of its proper divisors (945785946).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640693494 is a wasteful number, since it uses less digits than its factorization.

640693494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5084884 (or 5084881 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 45.

The square root of 640693494 is about 25311.9239490008. The cubic root of 640693494 is about 862.0850318875.

The spelling of 640693494 in words is "six hundred forty million, six hundred ninety-three thousand, four hundred ninety-four".