216561340 has 24 divisors (see below), whose sum is σ = 458255952. Its totient is φ = 85962240.

The previous prime is 216561337. The next prime is 216561341. The reversal of 216561340 is 43165612.

It is a junction number, because it is equal to n+sod(n) for n = 216561299 and 216561308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216561341) 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, 38709 + ... + 43948.

It is an arithmetic number, because the mean of its divisors is an integer number (19093998).

Almost surely, 2^216561340 is an apocalyptic number.

216561340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216561340 is an abundant number, since it is smaller than the sum of its proper divisors (241694612).

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

216561340 is a wasteful number, since it uses less digits than its factorization.

216561340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82797 (or 82795 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 216561340 is about 14716.0232399925. The cubic root of 216561340 is about 600.5193096587.

The spelling of 216561340 in words is "two hundred sixteen million, five hundred sixty-one thousand, three hundred forty".