11510001561 has 4 divisors (see below), whose sum is σ = 15346668752. Its totient is φ = 7673334372.

The previous prime is 11510001499. The next prime is 11510001599. The reversal of 11510001561 is 16510001511.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 11510001561 - 2⁶ = 11510001497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11510021561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1918333591 + ... + 1918333596.

It is an arithmetic number, because the mean of its divisors is an integer number (3836667188).

Almost surely, 2^11510001561 is an apocalyptic number.

It is an amenable number.

11510001561 is a deficient number, since it is larger than the sum of its proper divisors (3836667191).

11510001561 is an equidigital number, since it uses as much as digits as its factorization.

11510001561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3836667190.

The product of its (nonzero) digits is 150, while the sum is 21.

The spelling of 11510001561 in words is "eleven billion, five hundred ten million, one thousand, five hundred sixty-one".