20906387 has 2 divisors, whose sum is σ = 20906388. Its totient is φ = 20906386.

The previous prime is 20906377. The next prime is 20906401. The reversal of 20906387 is 78360902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20906387 - 2⁴ = 20906371 is a prime.

It is not a weakly prime, because it can be changed into another prime (20906317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10453193 + 10453194.

It is an arithmetic number, because the mean of its divisors is an integer number (10453194).

Almost surely, 2^20906387 is an apocalyptic number.

20906387 is a deficient number, since it is larger than the sum of its proper divisors (1).

20906387 is an equidigital number, since it uses as much as digits as its factorization.

20906387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 20906387 is about 4572.3502709219. The cubic root of 20906387 is about 275.4818527292.

The spelling of 20906387 in words is "twenty million, nine hundred six thousand, three hundred eighty-seven".