661715 has 8 divisors (see below), whose sum is σ = 803520. Its totient is φ = 523072.

The previous prime is 661697. The next prime is 661721. The reversal of 661715 is 517166.

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 661715 - 2⁸ = 661459 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299 + ... + 1188.

It is an arithmetic number, because the mean of its divisors is an integer number (100440).

2⁶⁶¹⁷¹⁵ is an apocalyptic number.

661715 is a deficient number, since it is larger than the sum of its proper divisors (141805).

661715 is a wasteful number, since it uses less digits than its factorization.

661715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581.

The product of its digits is 1260, while the sum is 26.

The square root of 661715 is about 813.4586652068. The cubic root of 661715 is about 87.1412248066.

The spelling of 661715 in words is "six hundred sixty-one thousand, seven hundred fifteen".