216388100 has 18 divisors (see below), whose sum is σ = 469562394. Its totient is φ = 86555200.

The previous prime is 216388097. The next prime is 216388127. The reversal of 216388100 is 1883612.

It can be written as a sum of positive squares in 3 ways, for example, as 3928324 + 212459776 = 1982^2 + 14576^2 .

It is a super-2 number, since 2×216388100² = 93647619643220000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1081841 + ... + 1082040.

Almost surely, 2^216388100 is an apocalyptic number.

216388100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216388100 is an abundant number, since it is smaller than the sum of its proper divisors (253174294).

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

216388100 is a wasteful number, since it uses less digits than its factorization.

216388100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2163895 (or 2163888 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 216388100 is about 14710.1359613023. The cubic root of 216388100 is about 600.3591368435.

The spelling of 216388100 in words is "two hundred sixteen million, three hundred eighty-eight thousand, one hundred".