21285120637 has 8 divisors (see below), whose sum is σ = 23231668032. Its totient is φ = 19340496000.

The previous prime is 21285120613. The next prime is 21285120643. The reversal of 21285120637 is 73602158212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21285120637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21285120596 and 21285120605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285120697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 457489 + ... + 501862.

It is an arithmetic number, because the mean of its divisors is an integer number (2903958504).

Almost surely, 2^21285120637 is an apocalyptic number.

It is an amenable number.

21285120637 is a deficient number, since it is larger than the sum of its proper divisors (1946547395).

21285120637 is a wasteful number, since it uses less digits than its factorization.

21285120637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 961379.

The product of its (nonzero) digits is 40320, while the sum is 37.

Adding to 21285120637 its reverse (73602158212), we get a palindrome (94887278849).

The spelling of 21285120637 in words is "twenty-one billion, two hundred eighty-five million, one hundred twenty thousand, six hundred thirty-seven".