21851037 has 12 divisors (see below), whose sum is σ = 33990684. Its totient is φ = 13446720.

The previous prime is 21851033. The next prime is 21851041. The reversal of 21851037 is 73015812.

It is an interprime number because it is at equal distance from previous prime (21851033) and next prime (21851041).

It can be written as a sum of positive squares in 2 ways, for example, as 3006756 + 18844281 = 1734^2 + 4341^2 .

It is not a de Polignac number, because 21851037 - 2² = 21851033 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21851037.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21851033) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 93264 + ... + 93497.

It is an arithmetic number, because the mean of its divisors is an integer number (2832557).

Almost surely, 2^21851037 is an apocalyptic number.

It is an amenable number.

21851037 is a deficient number, since it is larger than the sum of its proper divisors (12139647).

21851037 is a wasteful number, since it uses less digits than its factorization.

21851037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186780 (or 186777 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 21851037 is about 4674.5092790581. The cubic root of 21851037 is about 279.5700757576.

Adding to 21851037 its reverse (73015812), we get a palindrome (94866849).

The spelling of 21851037 in words is "twenty-one million, eight hundred fifty-one thousand, thirty-seven".