521661073 has 8 divisors (see below), whose sum is σ = 525389760. Its totient is φ = 517939920.

The previous prime is 521661071. The next prime is 521661097. The reversal of 521661073 is 370166125.

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 521661073 - 2¹ = 521661071 is a prime.

It is a super-2 number, since 2×521661073² = 544260550167022658, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521661071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 242583 + ... + 244723.

It is an arithmetic number, because the mean of its divisors is an integer number (65673720).

Almost surely, 2^521661073 is an apocalyptic number.

It is an amenable number.

521661073 is a deficient number, since it is larger than the sum of its proper divisors (3728687).

521661073 is a wasteful number, since it uses less digits than its factorization.

521661073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3767.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 521661073 is about 22839.9008973332. The cubic root of 521661073 is about 805.0004876352. Note that the first 3 decimals are identical.

It can be divided in two parts, 52 and 1661073, that multiplied together give a triangular number (86375796 = T₁₃₁₄₃).

The spelling of 521661073 in words is "five hundred twenty-one million, six hundred sixty-one thousand, seventy-three".