661534 has 4 divisors (see below), whose sum is σ = 992304. Its totient is φ = 330766.

The previous prime is 661517. The next prime is 661541. The reversal of 661534 is 435166.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 661499 and 661508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165382 + ... + 165385.

It is an arithmetic number, because the mean of its divisors is an integer number (248076).

2⁶⁶¹⁵³⁴ is an apocalyptic number.

661534 is a deficient number, since it is larger than the sum of its proper divisors (330770).

661534 is a wasteful number, since it uses less digits than its factorization.

661534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330769.

The product of its digits is 2160, while the sum is 25.

The square root of 661534 is about 813.3474042499. The cubic root of 661534 is about 87.1332787875.

It can be divided in two parts, 66 and 1534, that added together give a square (1600 = 40²).

The spelling of 661534 in words is "six hundred sixty-one thousand, five hundred thirty-four".