25991040 has 64 divisors (see below), whose sum is σ = 82852560. Its totient is φ = 6930432.

The previous prime is 25991039. The next prime is 25991071. The reversal of 25991040 is 4019952.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 25990989 and 25991007.

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, 4849 + ... + 8688.

Almost surely, 2^25991040 is an apocalyptic number.

25991040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25991040 is an abundant number, since it is smaller than the sum of its proper divisors (56861520).

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

25991040 is a wasteful number, since it uses less digits than its factorization.

25991040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13559 (or 13547 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 25991040 is about 5098.1408375995. The cubic root of 25991040 is about 296.2155722068.

The spelling of 25991040 in words is "twenty-five million, nine hundred ninety-one thousand, forty".