21062740 has 24 divisors (see below), whose sum is σ = 44732520. Its totient is φ = 8329728.

The previous prime is 21062737. The next prime is 21062747. The reversal of 21062740 is 4726012.

It can be written as a sum of positive squares in 4 ways, for example, as 3640464 + 17422276 = 1908^2 + 4174^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21062747) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4137 + ... + 7696.

It is an arithmetic number, because the mean of its divisors is an integer number (1863855).

Almost surely, 2^21062740 is an apocalyptic number.

21062740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21062740 is an abundant number, since it is smaller than the sum of its proper divisors (23669780).

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

21062740 is a wasteful number, since it uses less digits than its factorization.

21062740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11931 (or 11929 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21062740 is about 4589.4160848631. The cubic root of 21062740 is about 276.1668982855.

Adding to 21062740 its reverse (4726012), we get a palindrome (25788752).

The spelling of 21062740 in words is "twenty-one million, sixty-two thousand, seven hundred forty".