21142880 has 96 divisors (see below), whose sum is σ = 56010528. Its totient is φ = 7475200.

The previous prime is 21142871. The next prime is 21142889. The reversal of 21142880 is 8824112.

It is an interprime number because it is at equal distance from previous prime (21142871) and next prime (21142889).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142889) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72014 + ... + 72306.

It is an arithmetic number, because the mean of its divisors is an integer number (583443).

Almost surely, 2^21142880 is an apocalyptic number.

21142880 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 21142880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28005264).

21142880 is an abundant number, since it is smaller than the sum of its proper divisors (34867648).

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

21142880 is a wasteful number, since it uses less digits than its factorization.

21142880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 352 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 21142880 is about 4598.1387538873. The cubic root of 21142880 is about 276.5167104015.

Adding to 21142880 its reverse (8824112), we get a palindrome (29966992).

It can be divided in two parts, 21142 and 880, that added together give a palindrome (22022).

The spelling of 21142880 in words is "twenty-one million, one hundred forty-two thousand, eight hundred eighty".