21769445 has 4 divisors (see below), whose sum is σ = 26123340. Its totient is φ = 17415552.

The previous prime is 21769417. The next prime is 21769453. The reversal of 21769445 is 54496712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9138529 + 12630916 = 3023^2 + 3554^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21769445 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21769399 and 21769408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2176940 + ... + 2176949.

It is an arithmetic number, because the mean of its divisors is an integer number (6530835).

Almost surely, 2^21769445 is an apocalyptic number.

It is an amenable number.

21769445 is a deficient number, since it is larger than the sum of its proper divisors (4353895).

21769445 is an equidigital number, since it uses as much as digits as its factorization.

21769445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4353894.

The product of its digits is 60480, while the sum is 38.

The square root of 21769445 is about 4665.7737836290. The cubic root of 21769445 is about 279.2216692199.

The spelling of 21769445 in words is "twenty-one million, seven hundred sixty-nine thousand, four hundred forty-five".