151821281 has 4 divisors (see below), whose sum is σ = 153324564. Its totient is φ = 150318000.

The previous prime is 151821277. The next prime is 151821283. The reversal of 151821281 is 182128151.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 182128151 = 7219 ⋅25229.

It can be written as a sum of positive squares in 2 ways, for example, as 79299025 + 72522256 = 8905^2 + 8516^2 .

It is a cyclic number.

It is not a de Polignac number, because 151821281 - 2² = 151821277 is a prime.

It is a super-2 number, since 2×151821281² = 46099402728961922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (151821283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 751490 + ... + 751691.

It is an arithmetic number, because the mean of its divisors is an integer number (38331141).

Almost surely, 2^151821281 is an apocalyptic number.

It is an amenable number.

151821281 is a deficient number, since it is larger than the sum of its proper divisors (1503283).

151821281 is a wasteful number, since it uses less digits than its factorization.

151821281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1503282.

The product of its digits is 1280, while the sum is 29.

The square root of 151821281 is about 12321.5778616215. The cubic root of 151821281 is about 533.4710836460.

The spelling of 151821281 in words is "one hundred fifty-one million, eight hundred twenty-one thousand, two hundred eighty-one".