210421247 has 4 divisors (see below), whose sum is σ = 210726456. Its totient is φ = 210116040.

The previous prime is 210421217. The next prime is 210421261. The reversal of 210421247 is 742124012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 210421247 - 2¹⁴ = 210404863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210421217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151568 + ... + 152949.

It is an arithmetic number, because the mean of its divisors is an integer number (52681614).

Almost surely, 2^210421247 is an apocalyptic number.

210421247 is a deficient number, since it is larger than the sum of its proper divisors (305209).

210421247 is an equidigital number, since it uses as much as digits as its factorization.

210421247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305208.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 210421247 is about 14505.9038670467. The cubic root of 210421247 is about 594.7893678094.

Adding to 210421247 its reverse (742124012), we get a palindrome (952545259).

The spelling of 210421247 in words is "two hundred ten million, four hundred twenty-one thousand, two hundred forty-seven".