21770180 has 48 divisors (see below), whose sum is σ = 47416320. Its totient is φ = 8390400.

The previous prime is 21770179. The next prime is 21770237. The reversal of 21770180 is 8107712.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 113885 + ... + 114075.

It is an arithmetic number, because the mean of its divisors is an integer number (987840).

Almost surely, 2^21770180 is an apocalyptic number.

21770180 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 21770180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23708160).

21770180 is an abundant number, since it is smaller than the sum of its proper divisors (25646140).

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

21770180 is a wasteful number, since it uses less digits than its factorization.

21770180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380 (or 378 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 26.

The square root of 21770180 is about 4665.8525480345. The cubic root of 21770180 is about 279.2248116307.

Adding to 21770180 its reverse (8107712), we get a palindrome (29877892).

It can be divided in two parts, 21770 and 180, that multiplied together give a triangular number (3918600 = T₂₇₉₉).

The spelling of 21770180 in words is "twenty-one million, seven hundred seventy thousand, one hundred eighty".