25643541 has 32 divisors (see below), whose sum is σ = 44015616. Its totient is φ = 12888000.

The previous prime is 25643539. The next prime is 25643543. The reversal of 25643541 is 14534652.

25643541 is a nontrivial binomial coefficient, being equal to C(7162, 2).

It is an interprime number because it is at equal distance from previous prime (25643539) and next prime (25643543).

It is not a de Polignac number, because 25643541 - 2¹ = 25643539 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 25643499 and 25643508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25643543) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 5371 + ... + 8951.

It is an arithmetic number, because the mean of its divisors is an integer number (1375488).

Almost surely, 2^25643541 is an apocalyptic number.

25643541 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

25643541 is the 7161-st triangular number and also the 3581-st hexagonal number.

It is an amenable number.

25643541 is a deficient number, since it is larger than the sum of its proper divisors (18372075).

25643541 is a wasteful number, since it uses less digits than its factorization.

25643541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3633.

The product of its digits is 14400, while the sum is 30.

The square root of 25643541 is about 5063.9452011253. The cubic root of 25643541 is about 294.8895152667.

Subtracting from 25643541 its reverse (14534652), we obtain a square (11108889 = 3333²).

It can be divided in two parts, 2564 and 3541, that added together give a triangular number (6105 = T₁₁₀).

The spelling of 25643541 in words is "twenty-five million, six hundred forty-three thousand, five hundred forty-one".