501501561 has 72 divisors (see below), whose sum is σ = 802660320. Its totient is φ = 278087040.

The previous prime is 501501551. The next prime is 501501607. The reversal of 501501561 is 165105105.

It is not a de Polignac number, because 501501561 - 2¹⁰ = 501500537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (501501551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 5634805 + ... + 5634893.

It is an arithmetic number, because the mean of its divisors is an integer number (11148060).

Almost surely, 2^501501561 is an apocalyptic number.

It is an amenable number.

501501561 is a deficient number, since it is larger than the sum of its proper divisors (301158759).

501501561 is a wasteful number, since it uses less digits than its factorization.

501501561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195 (or 165 counting only the distinct ones).

The product of its (nonzero) digits is 750, while the sum is 24.

The square root of 501501561 is about 22394.2305293127. The cubic root of 501501561 is about 794.4942584587.

Adding to 501501561 its reverse (165105105), we get a palindrome (666606666).

The spelling of 501501561 in words is "five hundred one million, five hundred one thousand, five hundred sixty-one".