151691 has 4 divisors (see below), whose sum is σ = 160632. Its totient is φ = 142752.

The previous prime is 151687. The next prime is 151693. The reversal of 151691 is 196151.

151691 = T₁₂₅ + T₁₂₆ + ... + T₁₄₁.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 196151 = 73 ⋅2687.

It is a cyclic number.

It is not a de Polignac number, because 151691 - 2² = 151687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (151693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4445 + ... + 4478.

It is an arithmetic number, because the mean of its divisors is an integer number (40158).

2¹⁵¹⁶⁹¹ is an apocalyptic number.

151691 is a deficient number, since it is larger than the sum of its proper divisors (8941).

151691 is an equidigital number, since it uses as much as digits as its factorization.

151691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8940.

The product of its digits is 270, while the sum is 23.

The square root of 151691 is about 389.4752880479. The cubic root of 151691 is about 53.3318445765.

The spelling of 151691 in words is "one hundred fifty-one thousand, six hundred ninety-one".