21160440 has 192 divisors, whose sum is σ = 81768960. Its totient is φ = 4821120.

The previous prime is 21160439. The next prime is 21160457. The reversal of 21160440 is 4406112.

21160440 is a `hidden beast` number, since 21 + 1 + 604 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 67885 + ... + 68195.

It is an arithmetic number, because the mean of its divisors is an integer number (425880).

Almost surely, 2^21160440 is an apocalyptic number.

21160440 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 21160440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40884480).

21160440 is an abundant number, since it is smaller than the sum of its proper divisors (60608520).

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

21160440 is a wasteful number, since it uses less digits than its factorization.

21160440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21160440 is about 4600.0478258383. The cubic root of 21160440 is about 276.5932419145.

Adding to 21160440 its reverse (4406112), we get a palindrome (25566552).

It can be divided in two parts, 21 and 160440, that added together give a triangular number (160461 = T₅₆₆).

The spelling of 21160440 in words is "twenty-one million, one hundred sixty thousand, four hundred forty".