1520371681 has 4 divisors (see below), whose sum is σ = 1520449812. Its totient is φ = 1520293552.

The previous prime is 1520371639. The next prime is 1520371687. The reversal of 1520371681 is 1861730251.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 865830625 + 654541056 = 29425^2 + 25584^2 .

It is a cyclic number.

It is not a de Polignac number, because 1520371681 - 2¹⁵ = 1520338913 is a prime.

It is a super-2 number, since 2×1520371681² = 4623060096773531522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1520371687) 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 3 ways as a sum of consecutive naturals, for example, 15951 + ... + 57403.

It is an arithmetic number, because the mean of its divisors is an integer number (380112453).

Almost surely, 2^1520371681 is an apocalyptic number.

It is an amenable number.

1520371681 is a deficient number, since it is larger than the sum of its proper divisors (78131).

1520371681 is an equidigital number, since it uses as much as digits as its factorization.

1520371681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78130.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 1520371681 is about 38991.9437961228. The cubic root of 1520371681 is about 1149.8731255115.

The spelling of 1520371681 in words is "one billion, five hundred twenty million, three hundred seventy-one thousand, six hundred eighty-one".