20845687 has 2 divisors, whose sum is σ = 20845688. Its totient is φ = 20845686.

The previous prime is 20845681. The next prime is 20845697. The reversal of 20845687 is 78654802.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20845687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20845681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10422843 + 10422844.

It is an arithmetic number, because the mean of its divisors is an integer number (10422844).

Almost surely, 2^20845687 is an apocalyptic number.

20845687 is a deficient number, since it is larger than the sum of its proper divisors (1).

20845687 is an equidigital number, since it uses as much as digits as its factorization.

20845687 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 107520, while the sum is 40.

The square root of 20845687 is about 4565.7077217010. The cubic root of 20845687 is about 275.2149812060.

The spelling of 20845687 in words is "twenty million, eight hundred forty-five thousand, six hundred eighty-seven".