640023120 has 480 divisors, whose sum is σ = 2525088384. Its totient is φ = 149299200.

The previous prime is 640023107. The next prime is 640023133. The reversal of 640023120 is 21320046.

It is a happy number.

640023120 is a `hidden beast` number, since 640 + 0 + 2 + 3 + 1 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (640023107) and next prime (640023133).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 640023093 and 640023102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8767404 + ... + 8767476.

Almost surely, 2^640023120 is an apocalyptic number.

640023120 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640023120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1262544192).

640023120 is an abundant number, since it is smaller than the sum of its proper divisors (1885065264).

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

640023120 is a wasteful number, since it uses less digits than its factorization.

640023120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 640023120 is about 25298.6782263422. The cubic root of 640023120 is about 861.7842530816.

Adding to 640023120 its reverse (21320046), we get a palindrome (661343166).

The spelling of 640023120 in words is "six hundred forty million, twenty-three thousand, one hundred twenty".