21343331 has 2 divisors, whose sum is σ = 21343332. Its totient is φ = 21343330.

The previous prime is 21343307. The next prime is 21343337. The reversal of 21343331 is 13334312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21343331 - 2¹⁸ = 21081187 is a prime.

It is a super-2 number, since 2×21343331² = 911075556351122, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21343337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10671665 + 10671666.

It is an arithmetic number, because the mean of its divisors is an integer number (10671666).

Almost surely, 2^21343331 is an apocalyptic number.

21343331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21343331 is an equidigital number, since it uses as much as digits as its factorization.

21343331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 20.

The square root of 21343331 is about 4619.8843059107. The cubic root of 21343331 is about 277.3878279422.

Subtracting from 21343331 its sum of digits (20), we obtain a triangular number (21343311 = T₆₅₃₃).

Adding to 21343331 its reverse (13334312), we get a palindrome (34677643).

The spelling of 21343331 in words is "twenty-one million, three hundred forty-three thousand, three hundred thirty-one".