20975971 has 2 divisors, whose sum is σ = 20975972. Its totient is φ = 20975970.

The previous prime is 20975939. The next prime is 20975987. The reversal of 20975971 is 17957902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20975971 - 2⁵ = 20975939 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20975371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10487985 + 10487986.

It is an arithmetic number, because the mean of its divisors is an integer number (10487986).

Almost surely, 2^20975971 is an apocalyptic number.

20975971 is a deficient number, since it is larger than the sum of its proper divisors (1).

20975971 is an equidigital number, since it uses as much as digits as its factorization.

20975971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39690, while the sum is 40.

The square root of 20975971 is about 4579.9531656994. The cubic root of 20975971 is about 275.7871486055.

The spelling of 20975971 in words is "twenty million, nine hundred seventy-five thousand, nine hundred seventy-one".