51561541 has 4 divisors (see below), whose sum is σ = 51630412. Its totient is φ = 51492672.

The previous prime is 51561529. The next prime is 51561551. The reversal of 51561541 is 14516515.

It is a happy number.

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 22896225 + 28665316 = 4785^2 + 5354^2 .

It is a cyclic number.

It is not a de Polignac number, because 51561541 - 2¹¹ = 51559493 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 (51561511) 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, 33300 + ... + 34813.

It is an arithmetic number, because the mean of its divisors is an integer number (12907603).

Almost surely, 2^51561541 is an apocalyptic number.

It is an amenable number.

51561541 is a deficient number, since it is larger than the sum of its proper divisors (68871).

51561541 is an equidigital number, since it uses as much as digits as its factorization.

51561541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68870.

The product of its digits is 3000, while the sum is 28.

The square root of 51561541 is about 7180.6365316732. The cubic root of 51561541 is about 372.1990807259.

The spelling of 51561541 in words is "fifty-one million, five hundred sixty-one thousand, five hundred forty-one".