216421515 has 24 divisors (see below), whose sum is σ = 377089440. Its totient is φ = 114822144.

The previous prime is 216421483. The next prime is 216421523. The reversal of 216421515 is 515124612.

216421515 is a `hidden beast` number, since 2 + 1 + 642 + 1 + 5 + 15 = 666.

216421515 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 216421515 - 2⁵ = 216421483 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3775 + ... + 21144.

It is an arithmetic number, because the mean of its divisors is an integer number (15712060).

Almost surely, 2^216421515 is an apocalyptic number.

216421515 is a deficient number, since it is larger than the sum of its proper divisors (160667925).

216421515 is a wasteful number, since it uses less digits than its factorization.

216421515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25123 (or 25120 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 216421515 is about 14711.2716989389. The cubic root of 216421515 is about 600.3900380622.

The spelling of 216421515 in words is "two hundred sixteen million, four hundred twenty-one thousand, five hundred fifteen".