65561090401 has 3 divisors (see below), whose sum is σ = 65561346451. Its totient is φ = 65560834352.

The previous prime is 65561090363. The next prime is 65561090411. The reversal of 65561090401 is 10409016556.

The square root of 65561090401 is 256049.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 64516508001 + 1044582400 = 254001^2 + 32320^2 .

It is not a de Polignac number, because 65561090401 - 2¹⁷ = 65560959329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65561090411) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 128025 + ... + 384073.

Almost surely, 2^65561090401 is an apocalyptic number.

65561090401 is the 256049-th square number.

65561090401 is the 128025-th centered octagonal number.

It is an amenable number.

65561090401 is a deficient number, since it is larger than the sum of its proper divisors (256050).

65561090401 is an frugal number, since it uses more digits than its factorization.

65561090401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512098 (or 256049 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 37.

The spelling of 65561090401 in words is "sixty-five billion, five hundred sixty-one million, ninety thousand, four hundred one".