661005034521 has 128 divisors (see below), whose sum is σ = 1081206497280. Its totient is φ = 355129049088.

The previous prime is 661005034511. The next prime is 661005034561. The reversal of 661005034521 is 125430500166.

661005034521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 661005034521 - 2³⁸ = 386127127577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661005034511) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 64945785 + ... + 64955961.

It is an arithmetic number, because the mean of its divisors is an integer number (8446925760).

Almost surely, 2^661005034521 is an apocalyptic number.

It is an amenable number.

661005034521 is a deficient number, since it is larger than the sum of its proper divisors (420201462759).

661005034521 is a wasteful number, since it uses less digits than its factorization.

661005034521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10375.

The product of its (nonzero) digits is 21600, while the sum is 33.

Adding to 661005034521 its reverse (125430500166), we get a palindrome (786435534687).

The spelling of 661005034521 in words is "six hundred sixty-one billion, five million, thirty-four thousand, five hundred twenty-one".