21343691 has 2 divisors, whose sum is σ = 21343692. Its totient is φ = 21343690.

The previous prime is 21343661. The next prime is 21343697. The reversal of 21343691 is 19634312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21343691 - 2¹⁴ = 21327307 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21343697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10671845 + 10671846.

It is an arithmetic number, because the mean of its divisors is an integer number (10671846).

Almost surely, 2^21343691 is an apocalyptic number.

21343691 is a deficient number, since it is larger than the sum of its proper divisors (1).

21343691 is an equidigital number, since it uses as much as digits as its factorization.

21343691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

The square root of 21343691 is about 4619.9232677611. The cubic root of 21343691 is about 277.3893875091.

The spelling of 21343691 in words is "twenty-one million, three hundred forty-three thousand, six hundred ninety-one".