201661920 has 96 divisors (see below), whose sum is σ = 705831840. Its totient is φ = 53775360.

The previous prime is 201661919. The next prime is 201661927. The reversal of 201661920 is 29166102.

201661920 is a `hidden beast` number, since 20 + 1 + 6 + 619 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201661927) 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, 19021 + ... + 27660.

It is an arithmetic number, because the mean of its divisors is an integer number (7352415).

Almost surely, 2^201661920 is an apocalyptic number.

201661920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

201661920 is an abundant number, since it is smaller than the sum of its proper divisors (504169920).

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

201661920 is a wasteful number, since it uses less digits than its factorization.

201661920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46705 (or 46691 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 201661920 is about 14200.7718100109. The cubic root of 201661920 is about 586.4189093871.

It can be divided in two parts, 2016 and 61920, that added together give a palindrome (63936).

The spelling of 201661920 in words is "two hundred one million, six hundred sixty-one thousand, nine hundred twenty".