281421021 has 16 divisors (see below), whose sum is σ = 432843264. Its totient is φ = 159307824.

The previous prime is 281421013. The next prime is 281421037. The reversal of 281421021 is 120124182.

It is not a de Polignac number, because 281421021 - 2³ = 281421013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281421011) 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 15 ways as a sum of consecutive naturals, for example, 60375 + ... + 64868.

It is an arithmetic number, because the mean of its divisors is an integer number (27052704).

Almost surely, 2^281421021 is an apocalyptic number.

281421021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

281421021 is a deficient number, since it is larger than the sum of its proper divisors (151422243).

281421021 is a wasteful number, since it uses less digits than its factorization.

281421021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125360.

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 281421021 is about 16775.6079174497. The cubic root of 281421021 is about 655.3181221812.

The spelling of 281421021 in words is "two hundred eighty-one million, four hundred twenty-one thousand, twenty-one".