21132880 has 40 divisors (see below), whose sum is σ = 50833800. Its totient is φ = 8160768.

The previous prime is 21132877. The next prime is 21132893. The reversal of 21132880 is 8823112.

It can be written as a sum of positive squares in 4 ways, for example, as 266256 + 20866624 = 516^2 + 4568^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2235 + ... + 6874.

It is an arithmetic number, because the mean of its divisors is an integer number (1270845).

Almost surely, 2^21132880 is an apocalyptic number.

21132880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21132880 is an abundant number, since it is smaller than the sum of its proper divisors (29700920).

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

21132880 is a wasteful number, since it uses less digits than its factorization.

21132880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9151 (or 9145 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 21132880 is about 4597.0512287770. The cubic root of 21132880 is about 276.4731085968.

Adding to 21132880 its reverse (8823112), we get a palindrome (29955992).

The spelling of 21132880 in words is "twenty-one million, one hundred thirty-two thousand, eight hundred eighty".