1601513521 has 4 divisors (see below), whose sum is σ = 1610361844. Its totient is φ = 1592665200.

The previous prime is 1601513519. The next prime is 1601513527. The reversal of 1601513521 is 1253151061.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 165482496 + 1436031025 = 12864^2 + 37895^2 .

It is a cyclic number.

It is not a de Polignac number, because 1601513521 - 2¹ = 1601513519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1601513527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4423890 + ... + 4424251.

It is an arithmetic number, because the mean of its divisors is an integer number (402590461).

Almost surely, 2^1601513521 is an apocalyptic number.

It is an amenable number.

1601513521 is a deficient number, since it is larger than the sum of its proper divisors (8848323).

1601513521 is an equidigital number, since it uses as much as digits as its factorization.

1601513521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8848322.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 1601513521 is about 40018.9145405020. The cubic root of 1601513521 is about 1169.9757759126.

Adding to 1601513521 its reverse (1253151061), we get a palindrome (2854664582).

The spelling of 1601513521 in words is "one billion, six hundred one million, five hundred thirteen thousand, five hundred twenty-one".