21347771 has 2 divisors, whose sum is σ = 21347772. Its totient is φ = 21347770.

The previous prime is 21347723. The next prime is 21347791. The reversal of 21347771 is 17774312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21347771 - 2⁶ = 21347707 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21347701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10673885 + 10673886.

It is an arithmetic number, because the mean of its divisors is an integer number (10673886).

Almost surely, 2^21347771 is an apocalyptic number.

21347771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21347771 is an equidigital number, since it uses as much as digits as its factorization.

21347771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8232, while the sum is 32.

The square root of 21347771 is about 4620.3648124364. The cubic root of 21347771 is about 277.4070613749.

The spelling of 21347771 in words is "twenty-one million, three hundred forty-seven thousand, seven hundred seventy-one".