216021390 has 32 divisors (see below), whose sum is σ = 558333216. Its totient is φ = 53174400.

The previous prime is 216021389. The next prime is 216021391. The reversal of 216021390 is 93120612.

It is an interprime number because it is at equal distance from previous prime (216021389) and next prime (216021391).

It is a self number, because there is not a number n which added to its sum of digits gives 216021390.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216021391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 276561 + ... + 277340.

It is an arithmetic number, because the mean of its divisors is an integer number (17447913).

Almost surely, 2^216021390 is an apocalyptic number.

216021390 is an abundant number, since it is smaller than the sum of its proper divisors (342311826).

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

216021390 is a wasteful number, since it uses less digits than its factorization.

216021390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553924.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 216021390 is about 14697.6661412620. Note that the first 3 decimals coincide. The cubic root of 216021390 is about 600.0198049018.

The spelling of 216021390 in words is "two hundred sixteen million, twenty-one thousand, three hundred ninety".