5511265721 has 4 divisors (see below), whose sum is σ = 5935209252. Its totient is φ = 5087322192.

The previous prime is 5511265693. The next prime is 5511265769. The reversal of 5511265721 is 1275621155.

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 1731475321 + 3779790400 = 41611^2 + 61480^2 .

It is a cyclic number.

It is not a de Polignac number, because 5511265721 - 2²² = 5507071417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5511265421) 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, 211971746 + ... + 211971771.

It is an arithmetic number, because the mean of its divisors is an integer number (1483802313).

Almost surely, 2^5511265721 is an apocalyptic number.

It is an amenable number.

5511265721 is a deficient number, since it is larger than the sum of its proper divisors (423943531).

5511265721 is a wasteful number, since it uses less digits than its factorization.

5511265721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423943530.

The product of its digits is 21000, while the sum is 35.

The square root of 5511265721 is about 74237.8994921058. The cubic root of 5511265721 is about 1766.3785553941.

Adding to 5511265721 its reverse (1275621155), we get a palindrome (6786886876).

The spelling of 5511265721 in words is "five billion, five hundred eleven million, two hundred sixty-five thousand, seven hundred twenty-one".