287424221 has 4 divisors (see below), whose sum is σ = 328484832. Its totient is φ = 246363612.

The previous prime is 287424197. The next prime is 287424233. The reversal of 287424221 is 122424782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122424782 = 2 ⋅61212391.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-287424221 is a prime.

It is a super-2 number, since 2×287424221² = 165225365634913682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287424271) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20530295 + ... + 20530308.

It is an arithmetic number, because the mean of its divisors is an integer number (82121208).

Almost surely, 2^287424221 is an apocalyptic number.

It is an amenable number.

287424221 is a deficient number, since it is larger than the sum of its proper divisors (41060611).

287424221 is an equidigital number, since it uses as much as digits as its factorization.

287424221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41060610.

The product of its digits is 14336, while the sum is 32.

The square root of 287424221 is about 16953.5902097461. The cubic root of 287424221 is about 659.9450681248.

The spelling of 287424221 in words is "two hundred eighty-seven million, four hundred twenty-four thousand, two hundred twenty-one".