21238671 has 4 divisors (see below), whose sum is σ = 28318232. Its totient is φ = 14159112.

The previous prime is 21238669. The next prime is 21238681. The reversal of 21238671 is 17683212.

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

It is not a de Polignac number, because 21238671 - 2¹ = 21238669 is a prime.

It is a super-2 number, since 2×21238671² = 902162291692482, 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 (21238601) 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 3 ways as a sum of consecutive naturals, for example, 3539776 + ... + 3539781.

It is an arithmetic number, because the mean of its divisors is an integer number (7079558).

Almost surely, 2^21238671 is an apocalyptic number.

21238671 is a deficient number, since it is larger than the sum of its proper divisors (7079561).

21238671 is an equidigital number, since it uses as much as digits as its factorization.

21238671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7079560.

The product of its digits is 4032, while the sum is 30.

The square root of 21238671 is about 4608.5432622468. The cubic root of 21238671 is about 276.9336815087.

It can be divided in two parts, 212 and 38671, that added together give a palindrome (38883).

The spelling of 21238671 in words is "twenty-one million, two hundred thirty-eight thousand, six hundred seventy-one".