21122725 has 24 divisors (see below), whose sum is σ = 28525952. Its totient is φ = 15422400.

The previous prime is 21122719. The next prime is 21122743. The reversal of 21122725 is 52722112.

It is not a de Polignac number, because 21122725 - 2¹¹ = 21120677 is a prime.

It is a super-2 number, since 2×21122725² = 892339022851250, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21122696 and 21122705.

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 33160 + ... + 33790.

Almost surely, 2^21122725 is an apocalyptic number.

21122725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21122725 is a deficient number, since it is larger than the sum of its proper divisors (7403227).

21122725 is a wasteful number, since it uses less digits than its factorization.

21122725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757 (or 752 counting only the distinct ones).

The product of its digits is 560, while the sum is 22.

The square root of 21122725 is about 4595.9465836757. The cubic root of 21122725 is about 276.4288168857.

Adding to 21122725 its reverse (52722112), we get a palindrome (73844837).

The spelling of 21122725 in words is "twenty-one million, one hundred twenty-two thousand, seven hundred twenty-five".