216406556 has 12 divisors (see below), whose sum is σ = 381220560. Its totient is φ = 107486400.

The previous prime is 216406511. The next prime is 216406571. The reversal of 216406556 is 655604612.

It is a super-2 number, since 2×216406556² = 93663594959562272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 178541 + ... + 179748.

It is an arithmetic number, because the mean of its divisors is an integer number (31768380).

Almost surely, 2^216406556 is an apocalyptic number.

It is an amenable number.

216406556 is a deficient number, since it is larger than the sum of its proper divisors (164814004).

216406556 is a wasteful number, since it uses less digits than its factorization.

216406556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358444 (or 358442 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 216406556 is about 14710.7632704765. The cubic root of 216406556 is about 600.3762048080.

The spelling of 216406556 in words is "two hundred sixteen million, four hundred six thousand, five hundred fifty-six".