621281 has 6 divisors (see below), whose sum is σ = 656082. Its totient is φ = 588240.

The previous prime is 621259. The next prime is 621289. The reversal of 621281 is 182126.

It can be written as a sum of positive squares in only one way, i.e., 577600 + 43681 = 760^2 + 209^2 .

It is not a de Polignac number, because 621281 - 2⁶ = 621217 is a prime.

It is a super-2 number, since 2×621281² = 771980161922, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 500 + ... + 1221.

It is an arithmetic number, because the mean of its divisors is an integer number (109347).

2⁶²¹²⁸¹ is an apocalyptic number.

621281 is the 353-rd centered decagonal number.

It is an amenable number.

621281 is a deficient number, since it is larger than the sum of its proper divisors (34801).

621281 is a wasteful number, since it uses less digits than its factorization.

621281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1759 (or 1740 counting only the distinct ones).

The product of its digits is 192, while the sum is 20.

The square root of 621281 is about 788.2138034823. The cubic root of 621281 is about 85.3288758387.

The spelling of 621281 in words is "six hundred twenty-one thousand, two hundred eighty-one".