7216521545 has 4 divisors (see below), whose sum is σ = 8659825860. Its totient is φ = 5773217232.

The previous prime is 7216521541. The next prime is 7216521547. The reversal of 7216521545 is 5451256127.

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 1809566521 + 5406955024 = 42539^2 + 73532^2 .

It is a cyclic number.

It is not a de Polignac number, because 7216521545 - 2² = 7216521541 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 7216521499 and 7216521508.

It is not an unprimeable number, because it can be changed into a prime (7216521541) 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, 721652150 + ... + 721652159.

It is an arithmetic number, because the mean of its divisors is an integer number (2164956465).

Almost surely, 2^7216521545 is an apocalyptic number.

It is an amenable number.

7216521545 is a deficient number, since it is larger than the sum of its proper divisors (1443304315).

7216521545 is a wasteful number, since it uses less digits than its factorization.

7216521545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1443304314.

The product of its digits is 84000, while the sum is 38.

The square root of 7216521545 is about 84950.1120952762. The cubic root of 7216521545 is about 1932.4546202164.

The spelling of 7216521545 in words is "seven billion, two hundred sixteen million, five hundred twenty-one thousand, five hundred forty-five".