216407421 has 6 divisors (see below), whose sum is σ = 312588510. Its totient is φ = 144271608.

The previous prime is 216407417. The next prime is 216407423. The reversal of 216407421 is 124704612.

216407421 is a `hidden beast` number, since 216 + 407 + 42 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 163481796 + 52925625 = 12786^2 + 7275^2 .

It is not a de Polignac number, because 216407421 - 2² = 216407417 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216407423) 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 5 ways as a sum of consecutive naturals, for example, 12022626 + ... + 12022643.

It is an arithmetic number, because the mean of its divisors is an integer number (52098085).

Almost surely, 2^216407421 is an apocalyptic number.

It is an amenable number.

216407421 is a deficient number, since it is larger than the sum of its proper divisors (96181089).

216407421 is a wasteful number, since it uses less digits than its factorization.

216407421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24045275 (or 24045272 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 216407421 is about 14710.7926706891. The cubic root of 216407421 is about 600.3770047294.

The spelling of 216407421 in words is "two hundred sixteen million, four hundred seven thousand, four hundred twenty-one".