216616540 has 24 divisors (see below), whose sum is σ = 519880032. Its totient is φ = 74268480.

The previous prime is 216616529. The next prime is 216616541. The reversal of 216616540 is 45616612.

216616540 = 1384² + 1385² + ... + 1488².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216616541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 773491 + ... + 773770.

It is an arithmetic number, because the mean of its divisors is an integer number (21661668).

Almost surely, 2^216616540 is an apocalyptic number.

216616540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216616540 is an abundant number, since it is smaller than the sum of its proper divisors (303263492).

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

216616540 is a wasteful number, since it uses less digits than its factorization.

216616540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1547277 (or 1547275 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 216616540 is about 14717.8986271818. The cubic root of 216616540 is about 600.5703280751.

It can be divided in two parts, 216616 and 540, that added together give a square (217156 = 466²).

The spelling of 216616540 in words is "two hundred sixteen million, six hundred sixteen thousand, five hundred forty".