25543731640 has 64 divisors (see below), whose sum is σ = 65840947200. Its totient is φ = 8736908928.

The previous prime is 25543731623. The next prime is 25543731641. The reversal of 25543731640 is 4613734552.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 25543731593 and 25543731602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25543731641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8457 + ... + 226183.

It is an arithmetic number, because the mean of its divisors is an integer number (1028764800).

Almost surely, 2^25543731640 is an apocalyptic number.

25543731640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25543731640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32920473600).

25543731640 is an abundant number, since it is smaller than the sum of its proper divisors (40297215560).

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

25543731640 is a wasteful number, since it uses less digits than its factorization.

25543731640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218164 (or 218160 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 40.

The spelling of 25543731640 in words is "twenty-five billion, five hundred forty-three million, seven hundred thirty-one thousand, six hundred forty".