640000023 has 8 divisors (see below), whose sum is σ = 918974448. Its totient is φ = 393846144.

The previous prime is 640000019. The next prime is 640000027. The reversal of 640000023 is 320000046.

It is an interprime number because it is at equal distance from previous prime (640000019) and next prime (640000027).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640000023 - 2² = 640000019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 639999957 and 640000011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640000027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8205090 + ... + 8205167.

It is an arithmetic number, because the mean of its divisors is an integer number (114871806).

Almost surely, 2^640000023 is an apocalyptic number.

640000023 is a deficient number, since it is larger than the sum of its proper divisors (278974425).

640000023 is a wasteful number, since it uses less digits than its factorization.

640000023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16410273.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 640000023 is about 25298.2217359244. The cubic root of 640000023 is about 861.7738863361.

Adding to 640000023 its reverse (320000046), we get a palindrome (960000069).

The spelling of 640000023 in words is "six hundred forty million, twenty-three", and thus it is an aban number.