501211561 has 8 divisors (see below), whose sum is σ = 553768704. Its totient is φ = 451218240.

The previous prime is 501211559. The next prime is 501211567. The reversal of 501211561 is 165112105.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 501211561 - 2¹ = 501211559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (501211567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 640545 + ... + 641326.

It is an arithmetic number, because the mean of its divisors is an integer number (69221088).

Almost surely, 2^501211561 is an apocalyptic number.

It is an amenable number.

501211561 is a deficient number, since it is larger than the sum of its proper divisors (52557143).

501211561 is a wasteful number, since it uses less digits than its factorization.

501211561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1281911.

The product of its (nonzero) digits is 300, while the sum is 22.

The square root of 501211561 is about 22387.7547110022. The cubic root of 501211561 is about 794.3410866122.

Adding to 501211561 its reverse (165112105), we get a palindrome (666323666).

The spelling of 501211561 in words is "five hundred one million, two hundred eleven thousand, five hundred sixty-one".