21240068 has 12 divisors (see below), whose sum is σ = 37871820. Its totient is φ = 10419552.

The previous prime is 21240049. The next prime is 21240073. The reversal of 21240068 is 86004212.

It can be written as a sum of positive squares in 2 ways, for example, as 9351364 + 11888704 = 3058^2 + 3448^2 .

It is a super-2 number, since 2×21240068² = 902280977289248, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49883 + ... + 50306.

It is an arithmetic number, because the mean of its divisors is an integer number (3155985).

Almost surely, 2^21240068 is an apocalyptic number.

It is an amenable number.

21240068 is a deficient number, since it is larger than the sum of its proper divisors (16631752).

21240068 is a wasteful number, since it uses less digits than its factorization.

21240068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100246 (or 100244 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 21240068 is about 4608.6948260869. The cubic root of 21240068 is about 276.9397532613.

The spelling of 21240068 in words is "twenty-one million, two hundred forty thousand, sixty-eight".