661507 has 16 divisors (see below), whose sum is σ = 843264. Its totient is φ = 508200.

The previous prime is 661483. The next prime is 661513. The reversal of 661507 is 705166.

It is not a de Polignac number, because 661507 - 2¹⁹ = 137219 is a prime.

It is a super-2 number, since 2×661507² = 875183022098, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661517) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9282 + ... + 9352.

It is an arithmetic number, because the mean of its divisors is an integer number (52704).

2⁶⁶¹⁵⁰⁷ is an apocalyptic number.

661507 is a deficient number, since it is larger than the sum of its proper divisors (181757).

661507 is an equidigital number, since it uses as much as digits as its factorization.

661507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 661507 is about 813.3308060070. The cubic root of 661507 is about 87.1320933455.

The spelling of 661507 in words is "six hundred sixty-one thousand, five hundred seven".