151661 has 4 divisors (see below), whose sum is σ = 155232. Its totient is φ = 148092.

The previous prime is 151651. The next prime is 151667. The reversal of 151661 is 166151.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 151661 - 2⁶ = 151597 is a prime.

It is a Duffinian number.

It is a Curzon number.

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 151661.

It is not an unprimeable number, because it can be changed into a prime (151667) 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, 1721 + ... + 1806.

It is an arithmetic number, because the mean of its divisors is an integer number (38808).

2¹⁵¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

151661 is a deficient number, since it is larger than the sum of its proper divisors (3571).

151661 is an equidigital number, since it uses as much as digits as its factorization.

151661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3570.

The product of its digits is 180, while the sum is 20.

The square root of 151661 is about 389.4367727886. The cubic root of 151661 is about 53.3283285234.

The spelling of 151661 in words is "one hundred fifty-one thousand, six hundred sixty-one".