5665138221 has 4 divisors (see below), whose sum is σ = 7553517632. Its totient is φ = 3776758812.

The previous prime is 5665138217. The next prime is 5665138261. The reversal of 5665138221 is 1228315665.

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 5665138221 - 2² = 5665138217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 5665138221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5665138261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 944189701 + ... + 944189706.

It is an arithmetic number, because the mean of its divisors is an integer number (1888379408).

Almost surely, 2^5665138221 is an apocalyptic number.

It is an amenable number.

5665138221 is a deficient number, since it is larger than the sum of its proper divisors (1888379411).

5665138221 is a wasteful number, since it uses less digits than its factorization.

5665138221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1888379410.

The product of its digits is 86400, while the sum is 39.

The square root of 5665138221 is about 75267.1124794887. The cubic root of 5665138221 is about 1782.6667745685. Note that the first 3 decimals are identical.

The spelling of 5665138221 in words is "five billion, six hundred sixty-five million, one hundred thirty-eight thousand, two hundred twenty-one".