20869987 has 2 divisors, whose sum is σ = 20869988. Its totient is φ = 20869986.

The previous prime is 20869967. The next prime is 20870023. The reversal of 20869987 is 78996802.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20869987 - 2⁷ = 20869859 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20869987.

It is not a weakly prime, because it can be changed into another prime (20869907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10434993 + 10434994.

It is an arithmetic number, because the mean of its divisors is an integer number (10434994).

Almost surely, 2^20869987 is an apocalyptic number.

20869987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20869987 is an equidigital number, since it uses as much as digits as its factorization.

20869987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 49.

The square root of 20869987 is about 4568.3680893728. The cubic root of 20869987 is about 275.3218798509.

The spelling of 20869987 in words is "twenty million, eight hundred sixty-nine thousand, nine hundred eighty-seven".