20947867 has 2 divisors, whose sum is σ = 20947868. Its totient is φ = 20947866.

The previous prime is 20947811. The next prime is 20947873. The reversal of 20947867 is 76874902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20947867 - 2⁷ = 20947739 is a prime.

It is not a weakly prime, because it can be changed into another prime (20947807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10473933 + 10473934.

It is an arithmetic number, because the mean of its divisors is an integer number (10473934).

Almost surely, 2^20947867 is an apocalyptic number.

20947867 is a deficient number, since it is larger than the sum of its proper divisors (1).

20947867 is an equidigital number, since it uses as much as digits as its factorization.

20947867 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 20947867 is about 4576.8839836727. The cubic root of 20947867 is about 275.6639252892.

The spelling of 20947867 in words is "twenty million, nine hundred forty-seven thousand, eight hundred sixty-seven".