21859836 has 24 divisors (see below), whose sum is σ = 52652544. Its totient is φ = 7051440.

The previous prime is 21859813. The next prime is 21859837. The reversal of 21859836 is 63895812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21859837) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29010 + ... + 29753.

It is an arithmetic number, because the mean of its divisors is an integer number (2193856).

Almost surely, 2^21859836 is an apocalyptic number.

It is an amenable number.

21859836 is an abundant number, since it is smaller than the sum of its proper divisors (30792708).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21859836 is a wasteful number, since it uses less digits than its factorization.

21859836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58801 (or 58799 counting only the distinct ones).

The product of its digits is 103680, while the sum is 42.

The square root of 21859836 is about 4675.4503526398. The cubic root of 21859836 is about 279.6075965853.

It can be divided in two parts, 2185 and 9836, that added together give a palindrome (12021).

The spelling of 21859836 in words is "twenty-one million, eight hundred fifty-nine thousand, eight hundred thirty-six".