201638651 has 4 divisors (see below), whose sum is σ = 204478704. Its totient is φ = 198798600.

The previous prime is 201638617. The next prime is 201638699. The reversal of 201638651 is 156836102.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201638651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201638351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1419920 + ... + 1420061.

It is an arithmetic number, because the mean of its divisors is an integer number (51119676).

Almost surely, 2^201638651 is an apocalyptic number.

201638651 is a deficient number, since it is larger than the sum of its proper divisors (2840053).

201638651 is an equidigital number, since it uses as much as digits as its factorization.

201638651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2840052.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 201638651 is about 14199.9524999206. The cubic root of 201638651 is about 586.3963536389.

The spelling of 201638651 in words is "two hundred one million, six hundred thirty-eight thousand, six hundred fifty-one".