201553666 has 8 divisors (see below), whose sum is σ = 320114700. Its totient is φ = 94848768.

The previous prime is 201553643. The next prime is 201553679. The reversal of 201553666 is 666355102.

It can be written as a sum of positive squares in 2 ways, for example, as 190854225 + 10699441 = 13815^2 + 3271^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (34), and also a Moran number because the ratio is a prime number: 5928049 = 201553666 / (2 + 0 + 1 + 5 + 5 + 3 + 6 + 6 + 6).

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 3 ways as a sum of consecutive naturals, for example, 2963991 + ... + 2964058.

Almost surely, 2^201553666 is an apocalyptic number.

201553666 is a deficient number, since it is larger than the sum of its proper divisors (118561034).

201553666 is a wasteful number, since it uses less digits than its factorization.

201553666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5928068.

The product of its (nonzero) digits is 32400, while the sum is 34.

The square root of 201553666 is about 14196.9597449595. The cubic root of 201553666 is about 586.3139588916.

The spelling of 201553666 in words is "two hundred one million, five hundred fifty-three thousand, six hundred sixty-six".