201661240 has 64 divisors (see below), whose sum is σ = 516533760. Its totient is φ = 70139520.

The previous prime is 201661177. The next prime is 201661241. The reversal of 201661240 is 42166102.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201661241) 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 15 ways as a sum of consecutive naturals, for example, 157 + ... + 20083.

It is an arithmetic number, because the mean of its divisors is an integer number (8070840).

Almost surely, 2^201661240 is an apocalyptic number.

201661240 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 201661240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (258266880).

201661240 is an abundant number, since it is smaller than the sum of its proper divisors (314872520).

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

201661240 is a wasteful number, since it uses less digits than its factorization.

201661240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19972 (or 19968 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 201661240 is about 14200.7478676301. The cubic root of 201661240 is about 586.4182502554.

The spelling of 201661240 in words is "two hundred one million, six hundred sixty-one thousand, two hundred forty".