21234740 has 12 divisors (see below), whose sum is σ = 44592996. Its totient is φ = 8493888.

The previous prime is 21234713. The next prime is 21234767. The reversal of 21234740 is 4743212.

It is an interprime number because it is at equal distance from previous prime (21234713) and next prime (21234767).

It can be written as a sum of positive squares in 2 ways, for example, as 2347024 + 18887716 = 1532^2 + 4346^2 .

It is a congruent number.

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, 530849 + ... + 530888.

It is an arithmetic number, because the mean of its divisors is an integer number (3716083).

Almost surely, 2^21234740 is an apocalyptic number.

21234740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21234740 is an abundant number, since it is smaller than the sum of its proper divisors (23358256).

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

21234740 is a wasteful number, since it uses less digits than its factorization.

21234740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1061746 (or 1061744 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 21234740 is about 4608.1167519932. The cubic root of 21234740 is about 276.9165948546.

Adding to 21234740 its reverse (4743212), we get a palindrome (25977952).

The spelling of 21234740 in words is "twenty-one million, two hundred thirty-four thousand, seven hundred forty".