521640652391 has 8 divisors (see below), whose sum is σ = 523944136320. Its totient is φ = 519337391328.

The previous prime is 521640652373. The next prime is 521640652397. The reversal of 521640652391 is 193256046125.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 521640652391 - 2¹⁴ = 521640636007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521640652397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6158570 + ... + 6242696.

It is an arithmetic number, because the mean of its divisors is an integer number (65493017040).

Almost surely, 2^521640652391 is an apocalyptic number.

521640652391 is a deficient number, since it is larger than the sum of its proper divisors (2303483929).

521640652391 is a wasteful number, since it uses less digits than its factorization.

521640652391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111433.

The product of its (nonzero) digits is 388800, while the sum is 44.

The spelling of 521640652391 in words is "five hundred twenty-one billion, six hundred forty million, six hundred fifty-two thousand, three hundred ninety-one".