216821478029 has 8 divisors (see below), whose sum is σ = 233511082392. Its totient is φ = 200133449280.

The previous prime is 216821478023. The next prime is 216821478031. The reversal of 216821478029 is 920874128612.

216821478029 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 1063086025 + 215758392004 = 32605^2 + 464498^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216821478029 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 (216821478023) 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 7 ways as a sum of consecutive naturals, for example, 99962 + ... + 666059.

It is an arithmetic number, because the mean of its divisors is an integer number (29188885299).

Almost surely, 2^216821478029 is an apocalyptic number.

It is an amenable number.

216821478029 is a deficient number, since it is larger than the sum of its proper divisors (16689604363).

216821478029 is a wasteful number, since it uses less digits than its factorization.

216821478029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 787807.

The product of its (nonzero) digits is 774144, while the sum is 50.

The spelling of 216821478029 in words is "two hundred sixteen billion, eight hundred twenty-one million, four hundred seventy-eight thousand, twenty-nine".