216979997 has 8 divisors (see below), whose sum is σ = 234562944. Its totient is φ = 199524528.

The previous prime is 216979991. The next prime is 216980003. The reversal of 216979997 is 799979612.

It is an interprime number because it is at equal distance from previous prime (216979991) and next prime (216980003).

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 216979997 - 2¹² = 216975901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216979991) 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, 28313 + ... + 35150.

It is an arithmetic number, because the mean of its divisors is an integer number (29320368).

Almost surely, 2^216979997 is an apocalyptic number.

It is an amenable number.

216979997 is a deficient number, since it is larger than the sum of its proper divisors (17582947).

216979997 is a wasteful number, since it uses less digits than its factorization.

216979997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63739.

The product of its digits is 3857868, while the sum is 59.

The square root of 216979997 is about 14730.2409009493. The cubic root of 216979997 is about 600.9060357729.

The spelling of 216979997 in words is "two hundred sixteen million, nine hundred seventy-nine thousand, nine hundred ninety-seven".