640970 has 16 divisors (see below), whose sum is σ = 1258848. Its totient is φ = 233040.

The previous prime is 640967. The next prime is 640973. The reversal of 640970 is 79046.

It is an interprime number because it is at equal distance from previous prime (640967) and next prime (640973).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2804 + ... + 3023.

It is an arithmetic number, because the mean of its divisors is an integer number (78678).

2⁶⁴⁰⁹⁷⁰ is an apocalyptic number.

640970 is a deficient number, since it is larger than the sum of its proper divisors (617878).

640970 is a wasteful number, since it uses less digits than its factorization.

640970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5845.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 640970 is about 800.6060204620. The cubic root of 640970 is about 86.2209031586.

The spelling of 640970 in words is "six hundred forty thousand, nine hundred seventy".