661526 has 16 divisors (see below), whose sum is σ = 1054944. Its totient is φ = 310464.

The previous prime is 661517. The next prime is 661541. The reversal of 661526 is 625166.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 661495 and 661504.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3260 + ... + 3456.

It is an arithmetic number, because the mean of its divisors is an integer number (65934).

2⁶⁶¹⁵²⁶ is an apocalyptic number.

661526 is a deficient number, since it is larger than the sum of its proper divisors (393418).

661526 is a wasteful number, since it uses less digits than its factorization.

661526 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295.

The product of its digits is 2160, while the sum is 26.

The square root of 661526 is about 813.3424862873. The cubic root of 661526 is about 87.1329275488.

The spelling of 661526 in words is "six hundred sixty-one thousand, five hundred twenty-six".