21347331 has 4 divisors (see below), whose sum is σ = 28463112. Its totient is φ = 14231552.

The previous prime is 21347329. The next prime is 21347363. The reversal of 21347331 is 13374312.

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 21347331 - 2¹ = 21347329 is a prime.

It is a super-2 number, since 2×21347331² = 911417081647122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21347371) 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, 3557886 + ... + 3557891.

It is an arithmetic number, because the mean of its divisors is an integer number (7115778).

Almost surely, 2^21347331 is an apocalyptic number.

21347331 is a deficient number, since it is larger than the sum of its proper divisors (7115781).

21347331 is an equidigital number, since it uses as much as digits as its factorization.

21347331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7115780.

The product of its digits is 1512, while the sum is 24.

The square root of 21347331 is about 4620.3171969033. The cubic root of 21347331 is about 277.4051554781.

The spelling of 21347331 in words is "twenty-one million, three hundred forty-seven thousand, three hundred thirty-one".