201661556 has 12 divisors (see below), whose sum is σ = 353629920. Its totient is φ = 100624440.

The previous prime is 201661553. The next prime is 201661567. The reversal of 201661556 is 655166102.

It is a super-2 number, since 2×201661556² = 81334766336682272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201661553) 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 3 ways as a sum of consecutive naturals, for example, 49376 + ... + 53303.

It is an arithmetic number, because the mean of its divisors is an integer number (29469160).

Almost surely, 2^201661556 is an apocalyptic number.

It is an amenable number.

201661556 is a deficient number, since it is larger than the sum of its proper divisors (151968364).

201661556 is a wasteful number, since it uses less digits than its factorization.

201661556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103174 (or 103172 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 201661556 is about 14200.7589938003. The cubic root of 201661556 is about 586.4185565580.

The spelling of 201661556 in words is "two hundred one million, six hundred sixty-one thousand, five hundred fifty-six".