21197836 has 12 divisors (see below), whose sum is σ = 40468680. Its totient is φ = 9635360.

The previous prime is 21197821. The next prime is 21197837. The reversal of 21197836 is 63879112.

It is a junction number, because it is equal to n+sod(n) for n = 21197795 and 21197804.

It is not an unprimeable number, because it can be changed into a prime (21197837) 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, 240841 + ... + 240928.

It is an arithmetic number, because the mean of its divisors is an integer number (3372390).

Almost surely, 2^21197836 is an apocalyptic number.

It is an amenable number.

21197836 is a deficient number, since it is larger than the sum of its proper divisors (19270844).

21197836 is a wasteful number, since it uses less digits than its factorization.

21197836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481784 (or 481782 counting only the distinct ones).

The product of its digits is 18144, while the sum is 37.

The square root of 21197836 is about 4604.1107719081. The cubic root of 21197836 is about 276.7560834188.

The spelling of 21197836 in words is "twenty-one million, one hundred ninety-seven thousand, eight hundred thirty-six".