25781666240 has 56 divisors (see below), whose sum is σ = 66973746672. Its totient is φ = 9375150080.

The previous prime is 25781666231. The next prime is 25781666279. The reversal of 25781666240 is 4266618752.

It is a super-2 number, since 2×25781666240² (a number of 22 digits) contains 22 as substring.

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, 3658649 + ... + 3665688.

It is an arithmetic number, because the mean of its divisors is an integer number (1195959762).

Almost surely, 2^25781666240 is an apocalyptic number.

25781666240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25781666240 is an abundant number, since it is smaller than the sum of its proper divisors (41192080432).

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

25781666240 is a wasteful number, since it uses less digits than its factorization.

25781666240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7324365 (or 7324355 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 47.

The spelling of 25781666240 in words is "twenty-five billion, seven hundred eighty-one million, six hundred sixty-six thousand, two hundred forty".