1511001561 has 4 divisors (see below), whose sum is σ = 2014668752. Its totient is φ = 1007334372.

The previous prime is 1511001551. The next prime is 1511001601. The reversal of 1511001561 is 1651001151.

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 1511001561 - 2¹³ = 1510993369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1511001521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 251833591 + ... + 251833596.

It is an arithmetic number, because the mean of its divisors is an integer number (503667188).

Almost surely, 2^1511001561 is an apocalyptic number.

It is an amenable number.

1511001561 is a deficient number, since it is larger than the sum of its proper divisors (503667191).

1511001561 is an equidigital number, since it uses as much as digits as its factorization.

1511001561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503667190.

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

The square root of 1511001561 is about 38871.6035300835. The cubic root of 1511001561 is about 1147.5060157933.

The spelling of 1511001561 in words is "one billion, five hundred eleven million, one thousand, five hundred sixty-one".