11531097820 has 24 divisors (see below), whose sum is σ = 26416697328. Its totient is φ = 4193126400.

The previous prime is 11531097811. The next prime is 11531097871. The reversal of 11531097820 is 2879013511.

It is a self number, because there is not a number n which added to its sum of digits gives 11531097820.

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, 26206821 + ... + 26207260.

It is an arithmetic number, because the mean of its divisors is an integer number (1100695722).

Almost surely, 2^11531097820 is an apocalyptic number.

11531097820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11531097820 is an abundant number, since it is smaller than the sum of its proper divisors (14885599508).

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

11531097820 is a wasteful number, since it uses less digits than its factorization.

11531097820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52414101 (or 52414099 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 37.

The spelling of 11531097820 in words is "eleven billion, five hundred thirty-one million, ninety-seven thousand, eight hundred twenty".