521879661 has 6 divisors (see below), whose sum is σ = 753826190. Its totient is φ = 347919768.

The previous prime is 521879639. The next prime is 521879671. The reversal of 521879661 is 166978125.

It can be written as a sum of positive squares in only one way, i.e., 521208900 + 670761 = 22830^2 + 819^2 .

It is not a de Polignac number, because 521879661 - 2⁶ = 521879597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521879671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28993306 + ... + 28993323.

Almost surely, 2^521879661 is an apocalyptic number.

It is an amenable number.

521879661 is a deficient number, since it is larger than the sum of its proper divisors (231946529).

521879661 is a wasteful number, since it uses less digits than its factorization.

521879661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57986635 (or 57986632 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 521879661 is about 22844.6856183227. The cubic root of 521879661 is about 805.1129098469.

The spelling of 521879661 in words is "five hundred twenty-one million, eight hundred seventy-nine thousand, six hundred sixty-one".