216387780 has 96 divisors (see below), whose sum is σ = 694600704. Its totient is φ = 49305984.

The previous prime is 216387779. The next prime is 216387797. The reversal of 216387780 is 87783612.

It is a Harshad number since it is a multiple of its sum of digits (42).

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 31 ways as a sum of consecutive naturals, for example, 185479 + ... + 186641.

It is an arithmetic number, because the mean of its divisors is an integer number (7235424).

Almost surely, 2^216387780 is an apocalyptic number.

216387780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216387780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (347300352).

216387780 is an abundant number, since it is smaller than the sum of its proper divisors (478212924).

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

216387780 is a wasteful number, since it uses less digits than its factorization.

216387780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1625 (or 1623 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 42.

The square root of 216387780 is about 14710.1250844444. The cubic root of 216387780 is about 600.3588409015.

The spelling of 216387780 in words is "two hundred sixteen million, three hundred eighty-seven thousand, seven hundred eighty".