3651540521 has 4 divisors (see below), whose sum is σ = 3736460112. Its totient is φ = 3566620932.

The previous prime is 3651540493. The next prime is 3651540533. The reversal of 3651540521 is 1250451563.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1250451563 = 1433 ⋅872611.

It is a cyclic number.

It is not a de Polignac number, because 3651540521 - 2⁶ = 3651540457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3651543521) 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, 42459731 + ... + 42459816.

It is an arithmetic number, because the mean of its divisors is an integer number (934115028).

Almost surely, 2^3651540521 is an apocalyptic number.

It is an amenable number.

3651540521 is a deficient number, since it is larger than the sum of its proper divisors (84919591).

3651540521 is an equidigital number, since it uses as much as digits as its factorization.

3651540521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84919590.

The product of its (nonzero) digits is 18000, while the sum is 32.

The square root of 3651540521 is about 60427.9779655087. The cubic root of 3651540521 is about 1539.8983068004.

The spelling of 3651540521 in words is "three billion, six hundred fifty-one million, five hundred forty thousand, five hundred twenty-one".