43251561 has 12 divisors (see below), whose sum is σ = 62859888. Its totient is φ = 28656504.

The previous prime is 43251521. The next prime is 43251583. The reversal of 43251561 is 16515234.

It is not a de Polignac number, because 43251561 - 2¹⁵ = 43218793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (43251511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13275 + ... + 16208.

It is an arithmetic number, because the mean of its divisors is an integer number (5238324).

Almost surely, 2^43251561 is an apocalyptic number.

It is an amenable number.

43251561 is a deficient number, since it is larger than the sum of its proper divisors (19608327).

43251561 is a wasteful number, since it uses less digits than its factorization.

43251561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29652 (or 29649 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 43251561 is about 6576.5918985444. The cubic root of 43251561 is about 351.0216705641.

Adding to 43251561 its reverse (16515234), we get a palindrome (59766795).

It can be divided in two parts, 4325 and 1561, that added together give a triangular number (5886 = T₁₀₈).

The spelling of 43251561 in words is "forty-three million, two hundred fifty-one thousand, five hundred sixty-one".