640611236 has 12 divisors (see below), whose sum is σ = 1125537840. Its totient is φ = 319029000.

The previous prime is 640611233. The next prime is 640611287. The reversal of 640611236 is 632116046.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 640611199 and 640611208.

It is not an unprimeable number, because it can be changed into a prime (640611233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 318026 + ... + 320033.

It is an arithmetic number, because the mean of its divisors is an integer number (93794820).

Almost surely, 2^640611236 is an apocalyptic number.

It is an amenable number.

640611236 is a deficient number, since it is larger than the sum of its proper divisors (484926604).

640611236 is a wasteful number, since it uses less digits than its factorization.

640611236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638314 (or 638312 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 640611236 is about 25310.2990104819. The cubic root of 640611236 is about 862.0481362288.

The spelling of 640611236 in words is "six hundred forty million, six hundred eleven thousand, two hundred thirty-six".