21025740 has 24 divisors (see below), whose sum is σ = 58872240. Its totient is φ = 5606848.

The previous prime is 21025729. The next prime is 21025751. The reversal of 21025740 is 4752012.

It is an interprime number because it is at equal distance from previous prime (21025729) and next prime (21025751).

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 7 ways as a sum of consecutive naturals, for example, 175155 + ... + 175274.

It is an arithmetic number, because the mean of its divisors is an integer number (2453010).

Almost surely, 2^21025740 is an apocalyptic number.

21025740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21025740 is an abundant number, since it is smaller than the sum of its proper divisors (37846500).

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

21025740 is a wasteful number, since it uses less digits than its factorization.

21025740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350441 (or 350439 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21025740 is about 4585.3832991365. The cubic root of 21025740 is about 276.0050933738.

Adding to 21025740 its reverse (4752012), we get a palindrome (25777752).

The spelling of 21025740 in words is "twenty-one million, twenty-five thousand, seven hundred forty".