21869737 has 4 divisors (see below), whose sum is σ = 21881556. Its totient is φ = 21857920.

The previous prime is 21869719. The next prime is 21869747. The reversal of 21869737 is 73796812.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 9960336 + 11909401 = 3156^2 + 3451^2 .

It is a cyclic number.

It is not a de Polignac number, because 21869737 - 2⁷ = 21869609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21869693 and 21869702.

It is not an unprimeable number, because it can be changed into a prime (21869747) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2464 + ... + 7057.

It is an arithmetic number, because the mean of its divisors is an integer number (5470389).

Almost surely, 2^21869737 is an apocalyptic number.

It is an amenable number.

21869737 is a deficient number, since it is larger than the sum of its proper divisors (11819).

21869737 is an equidigital number, since it uses as much as digits as its factorization.

21869737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11818.

The product of its digits is 127008, while the sum is 43.

The square root of 21869737 is about 4676.5090612550. The cubic root of 21869737 is about 279.6498045408.

The spelling of 21869737 in words is "twenty-one million, eight hundred sixty-nine thousand, seven hundred thirty-seven".