151681 has 2 divisors, whose sum is σ = 151682. Its totient is φ = 151680.

The previous prime is 151673. The next prime is 151687. The reversal of 151681 is 186151.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147456 + 4225 = 384^2 + 65^2 .

It is a cyclic number.

It is not a de Polignac number, because 151681 - 2³ = 151673 is a prime.

It is a super-2 number, since 2×151681² = 46014251522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (151687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 75840 + 75841.

It is an arithmetic number, because the mean of its divisors is an integer number (75841).

2¹⁵¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

151681 is a deficient number, since it is larger than the sum of its proper divisors (1).

151681 is an equidigital number, since it uses as much as digits as its factorization.

151681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 22.

The square root of 151681 is about 389.4624500513. The cubic root of 151681 is about 53.3306726103.

It can be divided in two parts, 151 and 681, that multiplied together give a triangular number (102831 = T₄₅₃).

The spelling of 151681 in words is "one hundred fifty-one thousand, six hundred eighty-one".