21862836 has 18 divisors (see below), whose sum is σ = 55264482. Its totient is φ = 7287600.

The previous prime is 21862829. The next prime is 21862861. The reversal of 21862836 is 63826812.

21862836 is a `hidden beast` number, since 21 + 8 + 628 + 3 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11902500 + 9960336 = 3450^2 + 3156^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 607301 = 21862836 / (2 + 1 + 8 + 6 + 2 + 8 + 3 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 21862836.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 303615 + ... + 303686.

It is an arithmetic number, because the mean of its divisors is an integer number (3070249).

Almost surely, 2^21862836 is an apocalyptic number.

It is an amenable number.

21862836 is an abundant number, since it is smaller than the sum of its proper divisors (33401646).

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

21862836 is a wasteful number, since it uses less digits than its factorization.

21862836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607311 (or 607306 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 21862836 is about 4675.7711663425. The cubic root of 21862836 is about 279.6203869285.

The spelling of 21862836 in words is "twenty-one million, eight hundred sixty-two thousand, eight hundred thirty-six".