21485641987 has 2 divisors, whose sum is σ = 21485641988. Its totient is φ = 21485641986.

The previous prime is 21485641967. The next prime is 21485642021. The reversal of 21485641987 is 78914658412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21485641987 - 2¹⁵ = 21485609219 is a prime.

It is not a weakly prime, because it can be changed into another prime (21485641967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10742820993 + 10742820994.

It is an arithmetic number, because the mean of its divisors is an integer number (10742820994).

Almost surely, 2^21485641987 is an apocalyptic number.

21485641987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21485641987 is an equidigital number, since it uses as much as digits as its factorization.

21485641987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3870720, while the sum is 55.

The spelling of 21485641987 in words is "twenty-one billion, four hundred eighty-five million, six hundred forty-one thousand, nine hundred eighty-seven".