21140180 has 48 divisors (see below), whose sum is σ = 47564496. Its totient is φ = 7864320.

The previous prime is 21140173. The next prime is 21140191. The reversal of 21140180 is 8104112.

21140180 = 418² + 419² + ... + 514².

It can be written as a sum of positive squares in 8 ways, for example, as 1674436 + 19465744 = 1294^2 + 4412^2 .

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

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, 32660 + ... + 33300.

It is an arithmetic number, because the mean of its divisors is an integer number (990927).

Almost surely, 2^21140180 is an apocalyptic number.

21140180 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 21140180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23782248).

21140180 is an abundant number, since it is smaller than the sum of its proper divisors (26424316).

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

21140180 is a wasteful number, since it uses less digits than its factorization.

21140180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764 (or 762 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 21140180 is about 4597.8451474577. The cubic root of 21140180 is about 276.5049392693.

Adding to 21140180 its reverse (8104112), we get a palindrome (29244292).

The spelling of 21140180 in words is "twenty-one million, one hundred forty thousand, one hundred eighty".