216506380 has 24 divisors (see below), whose sum is σ = 457459632. Its totient is φ = 86069952.

The previous prime is 216506377. The next prime is 216506399. The reversal of 216506380 is 83605612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29947 + ... + 36466.

It is an arithmetic number, because the mean of its divisors is an integer number (19060818).

Almost surely, 2^216506380 is an apocalyptic number.

216506380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216506380 is an abundant number, since it is smaller than the sum of its proper divisors (240953252).

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

216506380 is a wasteful number, since it uses less digits than its factorization.

216506380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66585 (or 66583 counting only the distinct ones).

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

The square root of 216506380 is about 14714.1557691904. The cubic root of 216506380 is about 600.4685044478.

The spelling of 216506380 in words is "two hundred sixteen million, five hundred six thousand, three hundred eighty".