21807741 has 4 divisors (see below), whose sum is σ = 29076992. Its totient is φ = 14538492.

The previous prime is 21807733. The next prime is 21807743. The reversal of 21807741 is 14770812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21807741 - 2³ = 21807733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21807699 and 21807708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21807743) 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, 3634621 + ... + 3634626.

It is an arithmetic number, because the mean of its divisors is an integer number (7269248).

Almost surely, 2^21807741 is an apocalyptic number.

It is an amenable number.

21807741 is a deficient number, since it is larger than the sum of its proper divisors (7269251).

21807741 is an equidigital number, since it uses as much as digits as its factorization.

21807741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7269250.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 21807741 is about 4669.8759084156. The cubic root of 21807741 is about 279.3853054369.

The spelling of 21807741 in words is "twenty-one million, eight hundred seven thousand, seven hundred forty-one".