501115561 has 4 divisors (see below), whose sum is σ = 505798992. Its totient is φ = 496432132.

The previous prime is 501115553. The next prime is 501115567. The reversal of 501115561 is 165511105.

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 a cyclic number.

It is not a de Polignac number, because 501115561 - 2³ = 501115553 is a prime.

It is a super-2 number, since 2×501115561² = 502233610952689442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (501115567) 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, 2341555 + ... + 2341768.

It is an arithmetic number, because the mean of its divisors is an integer number (126449748).

Almost surely, 2^501115561 is an apocalyptic number.

It is an amenable number.

501115561 is a deficient number, since it is larger than the sum of its proper divisors (4683431).

501115561 is a wasteful number, since it uses less digits than its factorization.

501115561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4683430.

The product of its (nonzero) digits is 750, while the sum is 25.

The square root of 501115561 is about 22385.6105791198. The cubic root of 501115561 is about 794.2903684328.

Adding to 501115561 its reverse (165511105), we get a palindrome (666626666).

The spelling of 501115561 in words is "five hundred one million, one hundred fifteen thousand, five hundred sixty-one".