216821742 has 8 divisors (see below), whose sum is σ = 433643496. Its totient is φ = 72273912.

The previous prime is 216821729. The next prime is 216821743. The reversal of 216821742 is 247128612.

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

216821742 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216821743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18068473 + ... + 18068484.

It is an arithmetic number, because the mean of its divisors is an integer number (54205437).

Almost surely, 2^216821742 is an apocalyptic number.

216821742 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216821742 is a wasteful number, since it uses less digits than its factorization.

216821742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36136962.

The product of its digits is 10752, while the sum is 33.

The square root of 216821742 is about 14724.8681488155. The cubic root of 216821742 is about 600.7599093788.

The spelling of 216821742 in words is "two hundred sixteen million, eight hundred twenty-one thousand, seven hundred forty-two".