216187901 has 8 divisors (see below), whose sum is σ = 221678424. Its totient is φ = 210749760.

The previous prime is 216187897. The next prime is 216187913. The reversal of 216187901 is 109781612.

It can be written as a sum of positive squares in 4 ways, for example, as 35688676 + 180499225 = 5974^2 + 13435^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 216187901 - 2² = 216187897 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216187981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4670 + ... + 21311.

It is an arithmetic number, because the mean of its divisors is an integer number (27709803).

Almost surely, 2^216187901 is an apocalyptic number.

It is an amenable number.

216187901 is a deficient number, since it is larger than the sum of its proper divisors (5490523).

216187901 is a wasteful number, since it uses less digits than its factorization.

216187901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26191.

The product of its (nonzero) digits is 6048, while the sum is 35.

The square root of 216187901 is about 14703.3295889060. The cubic root of 216187901 is about 600.1739319820.

The spelling of 216187901 in words is "two hundred sixteen million, one hundred eighty-seven thousand, nine hundred one".