521501381 has 2 divisors, whose sum is σ = 521501382. Its totient is φ = 521501380.

The previous prime is 521501369. The next prime is 521501419. The reversal of 521501381 is 183105125.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 506025025 + 15476356 = 22495^2 + 3934^2 .

It is a cyclic number.

It is not a de Polignac number, because 521501381 - 2⁶ = 521501317 is a prime.

It is a super-2 number, since 2×521501381² = 543927380769814322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 521501381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521501311) 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 as a sum of consecutive naturals, namely, 260750690 + 260750691.

It is an arithmetic number, because the mean of its divisors is an integer number (260750691).

Almost surely, 2^521501381 is an apocalyptic number.

It is an amenable number.

521501381 is a deficient number, since it is larger than the sum of its proper divisors (1).

521501381 is an equidigital number, since it uses as much as digits as its factorization.

521501381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1200, while the sum is 26.

The square root of 521501381 is about 22836.4047301671. The cubic root of 521501381 is about 804.9183364300.

The spelling of 521501381 in words is "five hundred twenty-one million, five hundred one thousand, three hundred eighty-one".