25571640 has 32 divisors (see below), whose sum is σ = 76715280. Its totient is φ = 6819072.

The previous prime is 25571639. The next prime is 25571647. The reversal of 25571640 is 4617552.

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 = 25571598 and 25571607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25571647) 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, 106429 + ... + 106668.

Almost surely, 2^25571640 is an apocalyptic number.

25571640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25571640 is an abundant number, since it is smaller than the sum of its proper divisors (51143640).

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

25571640 is a wasteful number, since it uses less digits than its factorization.

25571640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213111 (or 213107 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 25571640 is about 5056.8409110827. The cubic root of 25571640 is about 294.6136472473.

The spelling of 25571640 in words is "twenty-five million, five hundred seventy-one thousand, six hundred forty".