20860391 has 2 divisors, whose sum is σ = 20860392. Its totient is φ = 20860390.

The previous prime is 20860387. The next prime is 20860393. The reversal of 20860391 is 19306802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20860391 - 2² = 20860387 is a prime.

Together with 20860393, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20860393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10430195 + 10430196.

It is an arithmetic number, because the mean of its divisors is an integer number (10430196).

Almost surely, 2^20860391 is an apocalyptic number.

20860391 is a deficient number, since it is larger than the sum of its proper divisors (1).

20860391 is an equidigital number, since it uses as much as digits as its factorization.

20860391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 20860391 is about 4567.3177029850. The cubic root of 20860391 is about 275.2796758030.

The spelling of 20860391 in words is "twenty million, eight hundred sixty thousand, three hundred ninety-one".