661015 has 8 divisors (see below), whose sum is σ = 804528. Its totient is φ = 521280.

The previous prime is 661009. The next prime is 661019. The reversal of 661015 is 510166.

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

It is not a de Polignac number, because 661015 - 2⁵ = 660983 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 660983 and 661001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661019) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 541 + ... + 1270.

It is an arithmetic number, because the mean of its divisors is an integer number (100566).

2⁶⁶¹⁰¹⁵ is an apocalyptic number.

661015 is a deficient number, since it is larger than the sum of its proper divisors (143513).

661015 is a wasteful number, since it uses less digits than its factorization.

661015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1889.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 661015 is about 813.0282897907. The cubic root of 661015 is about 87.1104863067.

It can be divided in two parts, 66 and 1015, that added together give a triangular number (1081 = T₄₆).

The spelling of 661015 in words is "six hundred sixty-one thousand, fifteen".