21485857687 has 16 divisors (see below), whose sum is σ = 25215835392. Its totient is φ = 17924074560.

The previous prime is 21485857651. The next prime is 21485857703. The reversal of 21485857687 is 78675858412.

It is a happy number.

It is not a de Polignac number, because 21485857687 - 2⁷ = 21485857559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21485851687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42433 + ... + 211594.

It is an arithmetic number, because the mean of its divisors is an integer number (1575989712).

Almost surely, 2^21485857687 is an apocalyptic number.

21485857687 is a deficient number, since it is larger than the sum of its proper divisors (3729977705).

21485857687 is a wasteful number, since it uses less digits than its factorization.

21485857687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254358.

The product of its digits is 30105600, while the sum is 61.

The spelling of 21485857687 in words is "twenty-one billion, four hundred eighty-five million, eight hundred fifty-seven thousand, six hundred eighty-seven".