12561475421 has 8 divisors (see below), whose sum is σ = 13704285888. Its totient is φ = 11418808000.

The previous prime is 12561475411. The next prime is 12561475427. The reversal of 12561475421 is 12457416521.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12561475421 - 2¹⁰ = 12561474397 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 (12561475427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 241061 + ... + 288501.

It is an arithmetic number, because the mean of its divisors is an integer number (1713035736).

Almost surely, 2^12561475421 is an apocalyptic number.

12561475421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12561475421 is a deficient number, since it is larger than the sum of its proper divisors (1142810467).

12561475421 is a wasteful number, since it uses less digits than its factorization.

12561475421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71523.

The product of its digits is 67200, while the sum is 38.

The spelling of 12561475421 in words is "twelve billion, five hundred sixty-one million, four hundred seventy-five thousand, four hundred twenty-one".