661512 has 32 divisors (see below), whose sum is σ = 1694880. Its totient is φ = 215040.

The previous prime is 661483. The next prime is 661513. The reversal of 661512 is 215166.

It is a happy number.

It is a super-2 number, since 2×661512² = 875196252288, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661512.

It is not an unprimeable number, because it can be changed into a prime (661513) by changing a digit.

661512 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 712 + ... + 1352.

It is an arithmetic number, because the mean of its divisors is an integer number (52965).

2⁶⁶¹⁵¹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (847440).

661512 is an abundant number, since it is smaller than the sum of its proper divisors (1033368).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661512 is a wasteful number, since it uses less digits than its factorization.

661512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 693 (or 689 counting only the distinct ones).

The product of its digits is 360, while the sum is 21.

The square root of 661512 is about 813.3338797812. Note that the first 3 decimals coincide. The cubic root of 661512 is about 87.1323128743.

Adding to 661512 its reverse (215166), we get a palindrome (876678).

The spelling of 661512 in words is "six hundred sixty-one thousand, five hundred twelve".