21085157536 has 24 divisors (see below), whose sum is σ = 41922414324. Its totient is φ = 10438195200.

The previous prime is 21085157497. The next prime is 21085157537. The reversal of 21085157536 is 63575158012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20158320400 + 926837136 = 141980^2 + 30444^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21085157492 and 21085157501.

It is not an unprimeable number, because it can be changed into a prime (21085157537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3258705 + ... + 3265168.

Almost surely, 2^21085157536 is an apocalyptic number.

It is an amenable number.

21085157536 is a deficient number, since it is larger than the sum of its proper divisors (20837256788).

21085157536 is a wasteful number, since it uses less digits than its factorization.

21085157536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6523984 (or 6523976 counting only the distinct ones).

The product of its (nonzero) digits is 252000, while the sum is 43.

The spelling of 21085157536 in words is "twenty-one billion, eighty-five million, one hundred fifty-seven thousand, five hundred thirty-six".