20586991 has 2 divisors, whose sum is σ = 20586992. Its totient is φ = 20586990.

The previous prime is 20586971. The next prime is 20587003. The reversal of 20586991 is 19968502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20586991 - 2¹³ = 20578799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20586971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10293495 + 10293496.

It is an arithmetic number, because the mean of its divisors is an integer number (10293496).

Almost surely, 2^20586991 is an apocalyptic number.

20586991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20586991 is an equidigital number, since it uses as much as digits as its factorization.

20586991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 20586991 is about 4537.2889482597. The cubic root of 20586991 is about 274.0717617993.

The spelling of 20586991 in words is "twenty million, five hundred eighty-six thousand, nine hundred ninety-one".