21085460 has 36 divisors (see below), whose sum is σ = 48676404. Its totient is φ = 7666560.

The previous prime is 21085453. The next prime is 21085511. The reversal of 21085460 is 6458012.

It can be written as a sum of positive squares in 2 ways, for example, as 15335056 + 5750404 = 3916^2 + 2398^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1937 + ... + 6776.

Almost surely, 2^21085460 is an apocalyptic number.

21085460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21085460 is an abundant number, since it is smaller than the sum of its proper divisors (27590944).

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

21085460 is a wasteful number, since it uses less digits than its factorization.

21085460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8744 (or 8731 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 21085460 is about 4591.8906781412. The cubic root of 21085460 is about 276.2661613635.

The spelling of 21085460 in words is "twenty-one million, eighty-five thousand, four hundred sixty".