20575991 has 2 divisors, whose sum is σ = 20575992. Its totient is φ = 20575990.

The previous prime is 20575981. The next prime is 20576009. The reversal of 20575991 is 19957502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20575991 - 2¹⁴ = 20559607 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20575981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10287995 + 10287996.

It is an arithmetic number, because the mean of its divisors is an integer number (10287996).

Almost surely, 2^20575991 is an apocalyptic number.

20575991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20575991 is an equidigital number, since it uses as much as digits as its factorization.

20575991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28350, while the sum is 38.

The square root of 20575991 is about 4536.0766087005. The cubic root of 20575991 is about 274.0229392768.

The spelling of 20575991 in words is "twenty million, five hundred seventy-five thousand, nine hundred ninety-one".