501611661550 has 24 divisors (see below), whose sum is σ = 933037491600. Its totient is φ = 200636105280.

The previous prime is 501611661547. The next prime is 501611661553. The reversal of 501611661550 is 55166116105.

It is an interprime number because it is at equal distance from previous prime (501611661547) and next prime (501611661553).

It is a super-2 number, since 2×501611661550² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (501611661553) 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 11 ways as a sum of consecutive naturals, for example, 1042911 + ... + 1445989.

It is an arithmetic number, because the mean of its divisors is an integer number (38876562150).

Almost surely, 2^501611661550 is an apocalyptic number.

501611661550 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

501611661550 is a deficient number, since it is larger than the sum of its proper divisors (431425830050).

501611661550 is a wasteful number, since it uses less digits than its factorization.

501611661550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427980 (or 427975 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 37.

Adding to 501611661550 its reverse (55166116105), we get a palindrome (556777777655).

The spelling of 501611661550 in words is "five hundred one billion, six hundred eleven million, six hundred sixty-one thousand, five hundred fifty".