21587036 has 24 divisors (see below), whose sum is σ = 39384576. Its totient is φ = 10341360.

The previous prime is 21587023. The next prime is 21587057. The reversal of 21587036 is 63078512.

It is a happy number.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21586993 and 21587011.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 12455 + ... + 14081.

It is an arithmetic number, because the mean of its divisors is an integer number (1641024).

Almost surely, 2^21587036 is an apocalyptic number.

It is an amenable number.

21587036 is a deficient number, since it is larger than the sum of its proper divisors (17797540).

21587036 is a wasteful number, since it uses less digits than its factorization.

21587036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1769 (or 1767 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21587036 is about 4646.1851017797. The cubic root of 21587036 is about 278.4396026093.

The spelling of 21587036 in words is "twenty-one million, five hundred eighty-seven thousand, thirty-six".