661525452321 has 32 divisors (see below), whose sum is σ = 895068195840. Its totient is φ = 434546520000.

The previous prime is 661525452319. The next prime is 661525452389. The reversal of 661525452321 is 123254525166.

It is not a de Polignac number, because 661525452321 - 2¹ = 661525452319 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661525452391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 86009086 + ... + 86016776.

It is an arithmetic number, because the mean of its divisors is an integer number (27970881120).

Almost surely, 2^661525452321 is an apocalyptic number.

It is an amenable number.

661525452321 is a deficient number, since it is larger than the sum of its proper divisors (233542743519).

661525452321 is a wasteful number, since it uses less digits than its factorization.

661525452321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9157.

The product of its digits is 432000, while the sum is 42.

Adding to 661525452321 its reverse (123254525166), we get a palindrome (784779977487).

The spelling of 661525452321 in words is "six hundred sixty-one billion, five hundred twenty-five million, four hundred fifty-two thousand, three hundred twenty-one".