201666051 has 8 divisors (see below), whose sum is σ = 298764560. Its totient is φ = 134444016.

The previous prime is 201666043. The next prime is 201666089. The reversal of 201666051 is 150666102.

It is a happy number.

It is not a de Polignac number, because 201666051 - 2³ = 201666043 is a prime.

It is a super-4 number, since 4×201666051⁴ (a number of 34 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 7469113 = 201666051 / (2 + 0 + 1 + 6 + 6 + 6 + 0 + 5 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201666041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3734530 + ... + 3734583.

It is an arithmetic number, because the mean of its divisors is an integer number (37345570).

Almost surely, 2^201666051 is an apocalyptic number.

201666051 is a deficient number, since it is larger than the sum of its proper divisors (97098509).

201666051 is an equidigital number, since it uses as much as digits as its factorization.

201666051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7469122 (or 7469116 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 201666051 is about 14200.9172591069. The cubic root of 201666051 is about 586.4229135805.

The spelling of 201666051 in words is "two hundred one million, six hundred sixty-six thousand, fifty-one".