25537661 has 8 divisors (see below), whose sum is σ = 26655480. Its totient is φ = 24435712.

The previous prime is 25537651. The next prime is 25537693. The reversal of 25537661 is 16673552.

It can be written as a sum of positive squares in 4 ways, for example, as 3728761 + 21808900 = 1931^2 + 4670^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25537661 - 2⁶ = 25537597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25537651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 620 + ... + 7173.

It is an arithmetic number, because the mean of its divisors is an integer number (3331935).

Almost surely, 2^25537661 is an apocalyptic number.

It is an amenable number.

25537661 is a deficient number, since it is larger than the sum of its proper divisors (1117819).

25537661 is a wasteful number, since it uses less digits than its factorization.

25537661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7935.

The product of its digits is 37800, while the sum is 35.

The square root of 25537661 is about 5053.4800880186. The cubic root of 25537661 is about 294.4830974875.

The spelling of 25537661 in words is "twenty-five million, five hundred thirty-seven thousand, six hundred sixty-one".