661480476421 has 4 divisors (see below), whose sum is σ = 661806491500. Its totient is φ = 661154461344.

The previous prime is 661480476409. The next prime is 661480476439. The reversal of 661480476421 is 124674084166.

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 582190364196 + 79290112225 = 763014^2 + 281585^2 .

It is a cyclic number.

It is not a de Polignac number, because 661480476421 - 2²¹ = 661478379269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661480476221) 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, 163004496 + ... + 163008553.

It is an arithmetic number, because the mean of its divisors is an integer number (165451622875).

Almost surely, 2^661480476421 is an apocalyptic number.

It is an amenable number.

661480476421 is a deficient number, since it is larger than the sum of its proper divisors (326015079).

661480476421 is a wasteful number, since it uses less digits than its factorization.

661480476421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326015078.

The product of its (nonzero) digits is 1548288, while the sum is 49.

The spelling of 661480476421 in words is "six hundred sixty-one billion, four hundred eighty million, four hundred seventy-six thousand, four hundred twenty-one".