1206616568521 has 27 divisors (see below), whose sum is σ = 1520016929703. Its totient is φ = 954606547440.

The previous prime is 1206616568513. The next prime is 1206616568537. The reversal of 1206616568521 is 1258656166021.

The square root of 1206616568521 is 1098461.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 178493575225 + 1028122993296 = 422485^2 + 1013964^2 .

It is not a de Polignac number, because 1206616568521 - 2³ = 1206616568513 is a prime.

It is a super-3 number, since 3×1206616568521³ (a number of 37 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1206616568501) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 99953916 + ... + 99965986.

Almost surely, 2^{1206616568521} is an apocalyptic number.

1206616568521 is the 1098461-st square number.

1206616568521 is the 549231-st centered octagonal number.

It is an amenable number.

1206616568521 is a deficient number, since it is larger than the sum of its proper divisors (313400361182).

1206616568521 is an frugal number, since it uses more digits than its factorization.

1206616568521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24182 (or 12091 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 49.

Multiplying 1206616568521 by its sum of digits (49), we get a square (59124211857529 = 7689227²).

1206616568521 divided by its sum of digits (49) gives a square (24624827929 = 156923²).

The spelling of 1206616568521 in words is "one trillion, two hundred six billion, six hundred sixteen million, five hundred sixty-eight thousand, five hundred twenty-one".