25661040 has 40 divisors (see below), whose sum is σ = 79549968. Its totient is φ = 6842880.

The previous prime is 25661029. The next prime is 25661071. The reversal of 25661040 is 4016652.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 25661040.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53221 + ... + 53700.

Almost surely, 2^25661040 is an apocalyptic number.

25661040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25661040 is an abundant number, since it is smaller than the sum of its proper divisors (53888928).

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

25661040 is a wasteful number, since it uses less digits than its factorization.

25661040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106937 (or 106931 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 25661040 is about 5065.6727095224. The cubic root of 25661040 is about 294.9565769659.

Adding to 25661040 its reverse (4016652), we get a palindrome (29677692).

The spelling of 25661040 in words is "twenty-five million, six hundred sixty-one thousand, forty".