21047051 has 2 divisors, whose sum is σ = 21047052. Its totient is φ = 21047050.

The previous prime is 21047017. The next prime is 21047077. The reversal of 21047051 is 15074012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21047051 - 2¹⁰ = 21046027 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21047951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10523525 + 10523526.

It is an arithmetic number, because the mean of its divisors is an integer number (10523526).

Almost surely, 2^21047051 is an apocalyptic number.

21047051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21047051 is an equidigital number, since it uses as much as digits as its factorization.

21047051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21047051 is about 4587.7065076136. The cubic root of 21047051 is about 276.0983117879.

The spelling of 21047051 in words is "twenty-one million, forty-seven thousand, fifty-one".