520071661 has 2 divisors, whose sum is σ = 520071662. Its totient is φ = 520071660.

The previous prime is 520071641. The next prime is 520071679. The reversal of 520071661 is 166170025.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 383415561 + 136656100 = 19581^2 + 11690^2 .

It is a cyclic number.

It is not a de Polignac number, because 520071661 - 2¹³ = 520063469 is a prime.

It is a super-3 number, since 3×520071661³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (520071631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260035830 + 260035831.

It is an arithmetic number, because the mean of its divisors is an integer number (260035831).

Almost surely, 2^520071661 is an apocalyptic number.

It is an amenable number.

520071661 is a deficient number, since it is larger than the sum of its proper divisors (1).

520071661 is an equidigital number, since it uses as much as digits as its factorization.

520071661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 520071661 is about 22805.0797192205. The cubic root of 520071661 is about 804.1820896658.

The spelling of 520071661 in words is "five hundred twenty million, seventy-one thousand, six hundred sixty-one".