201661651 has 2 divisors, whose sum is σ = 201661652. Its totient is φ = 201661650.

The previous prime is 201661637. The next prime is 201661673. The reversal of 201661651 is 156166102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 201661651 - 2⁵ = 201661619 is a prime.

It is not a weakly prime, because it can be changed into another prime (201661601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100830825 + 100830826.

It is an arithmetic number, because the mean of its divisors is an integer number (100830826).

Almost surely, 2^201661651 is an apocalyptic number.

201661651 is a deficient number, since it is larger than the sum of its proper divisors (1).

201661651 is an equidigital number, since it uses as much as digits as its factorization.

201661651 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 201661651 is about 14200.7623386915. The cubic root of 201661651 is about 586.4186486426.

The spelling of 201661651 in words is "two hundred one million, six hundred sixty-one thousand, six hundred fifty-one".