521408191396 has 27 divisors (see below), whose sum is σ = 918045532929. Its totient is φ = 259119116928.

The previous prime is 521408191393. The next prime is 521408191417. The reversal of 521408191396 is 693191804125.

It is a happy number.

The square root of 521408191396 is 722086.

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., 441015528100 + 80392663296 = 664090^2 + 283536^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521408191393) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 258505780 + ... + 258507796.

Almost surely, 2^521408191396 is an apocalyptic number.

521408191396 is the 722086-th square number.

It is an amenable number.

521408191396 is a deficient number, since it is larger than the sum of its proper divisors (396637341533).

521408191396 is an frugal number, since it uses more digits than its factorization.

521408191396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4396 (or 2198 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 49.

Multiplying 521408191396 by its sum of digits (49), we get a square (25549001378404 = 5054602²).

The spelling of 521408191396 in words is "five hundred twenty-one billion, four hundred eight million, one hundred ninety-one thousand, three hundred ninety-six".