25438721 has 16 divisors (see below), whose sum is σ = 32576640. Its totient is φ = 19284480.

The previous prime is 25438709. The next prime is 25438729. The reversal of 25438721 is 12783452.

It is a cyclic number.

It is not a de Polignac number, because 25438721 - 2¹⁰ = 25437697 is a prime.

It is a super-2 number, since 2×25438721² = 1294257052231682, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25438729) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1616 + ... + 7313.

It is an arithmetic number, because the mean of its divisors is an integer number (2036040).

Almost surely, 2^25438721 is an apocalyptic number.

It is an amenable number.

25438721 is a deficient number, since it is larger than the sum of its proper divisors (7137919).

25438721 is a wasteful number, since it uses less digits than its factorization.

25438721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8984.

The product of its digits is 13440, while the sum is 32.

The square root of 25438721 is about 5043.6812944515. The cubic root of 25438721 is about 294.1023021586.

The spelling of 25438721 in words is "twenty-five million, four hundred thirty-eight thousand, seven hundred twenty-one".