21288580 has 24 divisors (see below), whose sum is σ = 45376128. Its totient is φ = 8387808.

The previous prime is 21288577. The next prime is 21288601. The reversal of 21288580 is 8588212.

It is a happy 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, 6604 + ... + 9283.

It is an arithmetic number, because the mean of its divisors is an integer number (1890672).

Almost surely, 2^21288580 is an apocalyptic number.

21288580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21288580 is an abundant number, since it is smaller than the sum of its proper divisors (24087548).

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

21288580 is a wasteful number, since it uses less digits than its factorization.

21288580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15963 (or 15961 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 34.

The square root of 21288580 is about 4613.9549195891. The cubic root of 21288580 is about 277.1504350397.

The spelling of 21288580 in words is "twenty-one million, two hundred eighty-eight thousand, five hundred eighty".