21286120 has 16 divisors (see below), whose sum is σ = 47893860. Its totient is φ = 8514432.

The previous prime is 21286117. The next prime is 21286121. The reversal of 21286120 is 2168212.

It can be written as a sum of positive squares in 2 ways, for example, as 19945156 + 1340964 = 4466^2 + 1158^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21286091 and 21286100.

It is not an unprimeable number, because it can be changed into a prime (21286121) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 266037 + ... + 266116.

Almost surely, 2^21286120 is an apocalyptic number.

21286120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21286120 is an abundant number, since it is smaller than the sum of its proper divisors (26607740).

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

21286120 is a wasteful number, since it uses less digits than its factorization.

21286120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532164 (or 532160 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21286120 is about 4613.6883293088. The cubic root of 21286120 is about 277.1397592637.

The spelling of 21286120 in words is "twenty-one million, two hundred eighty-six thousand, one hundred twenty".