157661 has 8 divisors (see below), whose sum is σ = 182784. Its totient is φ = 133200.

The previous prime is 157649. The next prime is 157667. The reversal of 157661 is 166751.

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

It is a cyclic number.

It is not a de Polignac number, because 157661 - 2¹⁴ = 141277 is a prime.

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 157661.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 157661.

It is not an unprimeable number, because it can be changed into a prime (157667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 596 + ... + 818.

It is an arithmetic number, because the mean of its divisors is an integer number (22848).

2¹⁵⁷⁶⁶¹ is an apocalyptic number.

It is an amenable number.

157661 is a deficient number, since it is larger than the sum of its proper divisors (25123).

157661 is a wasteful number, since it uses less digits than its factorization.

157661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 331.

The product of its digits is 1260, while the sum is 26.

The square root of 157661 is about 397.0654857829. The cubic root of 157661 is about 54.0225100483.

It can be divided in two parts, 157 and 661, that added together give a palindrome (818).

The spelling of 157661 in words is "one hundred fifty-seven thousand, six hundred sixty-one".