20150640 has 160 divisors (see below), whose sum is σ = 73209600. Its totient is φ = 5080320.

The previous prime is 20150633. The next prime is 20150677. The reversal of 20150640 is 4605102.

It is a happy number.

20150640 is a `hidden beast` number, since 20 + 1 + 5 + 0 + 640 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40795 + ... + 41285.

It is an arithmetic number, because the mean of its divisors is an integer number (457560).

Almost surely, 2^20150640 is an apocalyptic number.

20150640 is a gapful number since it is divisible by the number (20) 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 20150640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36604800).

20150640 is an abundant number, since it is smaller than the sum of its proper divisors (53058960).

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

20150640 is a wasteful number, since it uses less digits than its factorization.

20150640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532 (or 520 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20150640 is about 4488.9464242737. The cubic root of 20150640 is about 272.1215575476.

Adding to 20150640 its reverse (4605102), we get a palindrome (24755742).

The spelling of 20150640 in words is "twenty million, one hundred fifty thousand, six hundred forty".