11531561040 has 240 divisors, whose sum is σ = 42329005056. Its totient is φ = 2800742400.

The previous prime is 11531561039. The next prime is 11531561047. The reversal of 11531561040 is 4016513511.

11531561040 is a `hidden beast` number, since 1 + 1 + 5 + 3 + 1 + 5 + 610 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a junction number, because it is equal to n+sod(n) for n = 11531560995 and 11531561013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11531561047) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 364245 + ... + 394635.

Almost surely, 2^11531561040 is an apocalyptic number.

11531561040 is a gapful number since it is divisible by the number (10) 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 11531561040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21164502528).

11531561040 is an abundant number, since it is smaller than the sum of its proper divisors (30797444016).

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

11531561040 is a wasteful number, since it uses less digits than its factorization.

11531561040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30458 (or 30449 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 11531561040 in words is "eleven billion, five hundred thirty-one million, five hundred sixty-one thousand, forty".