21446247 has 4 divisors (see below), whose sum is σ = 28595000. Its totient is φ = 14297496.

The previous prime is 21446237. The next prime is 21446261. The reversal of 21446247 is 74264412.

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

It is not a de Polignac number, because 21446247 - 2¹⁵ = 21413479 is a prime.

It is a super-3 number, since 3×21446247³ (a number of 23 digits) contains 333 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 (21446237) 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, 3574372 + ... + 3574377.

It is an arithmetic number, because the mean of its divisors is an integer number (7148750).

Almost surely, 2^21446247 is an apocalyptic number.

21446247 is a deficient number, since it is larger than the sum of its proper divisors (7148753).

21446247 is an equidigital number, since it uses as much as digits as its factorization.

21446247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7148752.

The product of its digits is 10752, while the sum is 30.

The square root of 21446247 is about 4631.0092852423. The cubic root of 21446247 is about 277.8329612617.

The spelling of 21446247 in words is "twenty-one million, four hundred forty-six thousand, two hundred forty-seven".