201731640 has 128 divisors (see below), whose sum is σ = 670360320. Its totient is φ = 48153600.

The previous prime is 201731623. The next prime is 201731653. The reversal of 201731640 is 46137102.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 201731640.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 87300 + ... + 89580.

It is an arithmetic number, because the mean of its divisors is an integer number (5237190).

Almost surely, 2^201731640 is an apocalyptic number.

201731640 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 201731640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335180160).

201731640 is an abundant number, since it is smaller than the sum of its proper divisors (468628680).

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

201731640 is a wasteful number, since it uses less digits than its factorization.

201731640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2373 (or 2369 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 201731640 is about 14203.2263940275. The cubic root of 201731640 is about 586.4864819124.

Adding to 201731640 its reverse (46137102), we get a palindrome (247868742).

The spelling of 201731640 in words is "two hundred one million, seven hundred thirty-one thousand, six hundred forty".