661159 has 4 divisors (see below), whose sum is σ = 662904. Its totient is φ = 659416.

The previous prime is 661139. The next prime is 661183. The reversal of 661159 is 951166.

661159 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 951166 = 2 ⋅475583.

It is a cyclic number.

It is not a de Polignac number, because 661159 - 2¹⁵ = 628391 is a prime.

It is a Duffinian number.

661159 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37 + ... + 1150.

It is an arithmetic number, because the mean of its divisors is an integer number (165726).

2⁶⁶¹¹⁵⁹ is an apocalyptic number.

661159 is a deficient number, since it is larger than the sum of its proper divisors (1745).

661159 is a wasteful number, since it uses less digits than its factorization.

661159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1744.

The product of its digits is 1620, while the sum is 28.

The square root of 661159 is about 813.1168427723. The cubic root of 661159 is about 87.1168114275.

It can be divided in two parts, 6611 and 59, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 661159 in words is "six hundred sixty-one thousand, one hundred fifty-nine".