7216620521561 has 16 divisors (see below), whose sum is σ = 7882059430080. Its totient is φ = 6552749244480.

The previous prime is 7216620521549. The next prime is 7216620521569. The reversal of 7216620521561 is 1651250266127.

It is a cyclic number.

It is not a de Polignac number, because 7216620521561 - 2¹⁸ = 7216620259417 is a prime.

It is a super-2 number, since 2×7216620521561² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7216620521569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37887815 + ... + 38077811.

It is an arithmetic number, because the mean of its divisors is an integer number (492628714380).

Almost surely, 2^{7216620521561} is an apocalyptic number.

It is an amenable number.

7216620521561 is a deficient number, since it is larger than the sum of its proper divisors (665438908519).

7216620521561 is a wasteful number, since it uses less digits than its factorization.

7216620521561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194104.

The product of its (nonzero) digits is 302400, while the sum is 44.

Adding to 7216620521561 its reverse (1651250266127), we get a palindrome (8867870787688).

The spelling of 7216620521561 in words is "seven trillion, two hundred sixteen billion, six hundred twenty million, five hundred twenty-one thousand, five hundred sixty-one".