216555401 has 8 divisors (see below), whose sum is σ = 229524480. Its totient is φ = 203611968.

The previous prime is 216555389. The next prime is 216555431. The reversal of 216555401 is 104555612.

It is a happy number.

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 216555401 - 2²⁶ = 149446537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216555431) 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, 12620 + ... + 24338.

It is an arithmetic number, because the mean of its divisors is an integer number (28690560).

Almost surely, 2^216555401 is an apocalyptic number.

It is an amenable number.

216555401 is a deficient number, since it is larger than the sum of its proper divisors (12969079).

216555401 is a wasteful number, since it uses less digits than its factorization.

216555401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12823.

The product of its (nonzero) digits is 6000, while the sum is 29.

The square root of 216555401 is about 14715.8214517573. The cubic root of 216555401 is about 600.5138200412.

The spelling of 216555401 in words is "two hundred sixteen million, five hundred fifty-five thousand, four hundred one".