661522 has 8 divisors (see below), whose sum is σ = 996156. Its totient is φ = 329472.

The previous prime is 661517. The next prime is 661541. The reversal of 661522 is 225166.

It can be written as a sum of positive squares in 2 ways, for example, as 594441 + 67081 = 771^2 + 259^2 .

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

It is a super-2 number, since 2×661522² = 875222712968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661493 and 661502.

It is an unprimeable number.

661522 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 238 + ... + 1174.

2⁶⁶¹⁵²² is an apocalyptic number.

661522 is a deficient number, since it is larger than the sum of its proper divisors (334634).

661522 is a wasteful number, since it uses less digits than its factorization.

661522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1292.

The product of its digits is 720, while the sum is 22.

The square root of 661522 is about 813.3400272949. The cubic root of 661522 is about 87.1327519284.

Adding to 661522 its reverse (225166), we get a palindrome (886688).

It can be divided in two parts, 6615 and 22, that multiplied together give a triangular number (145530 = T₅₃₉).

The spelling of 661522 in words is "six hundred sixty-one thousand, five hundred twenty-two".