3128401561 has 4 divisors (see below), whose sum is σ = 3130049124. Its totient is φ = 3126754000.

The previous prime is 3128401553. The next prime is 3128401597. The reversal of 3128401561 is 1651048213.

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 1579585536 + 1548816025 = 39744^2 + 39355^2 .

It is a cyclic number.

It is not a de Polignac number, because 3128401561 - 2³ = 3128401553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3128401061) 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, 820930 + ... + 824731.

It is an arithmetic number, because the mean of its divisors is an integer number (782512281).

Almost surely, 2^3128401561 is an apocalyptic number.

It is an amenable number.

3128401561 is a deficient number, since it is larger than the sum of its proper divisors (1647563).

3128401561 is a wasteful number, since it uses less digits than its factorization.

3128401561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1647562.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 3128401561 is about 55932.1156492404. The cubic root of 3128401561 is about 1462.5391420697.

Adding to 3128401561 its reverse (1651048213), we get a palindrome (4779449774).

The spelling of 3128401561 in words is "three billion, one hundred twenty-eight million, four hundred one thousand, five hundred sixty-one".