43661551 has 2 divisors, whose sum is σ = 43661552. Its totient is φ = 43661550.

The previous prime is 43661537. The next prime is 43661557. The reversal of 43661551 is 15516634.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 43661551 - 2¹³ = 43653359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43661557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21830775 + 21830776.

It is an arithmetic number, because the mean of its divisors is an integer number (21830776).

Almost surely, 2^43661551 is an apocalyptic number.

43661551 is a deficient number, since it is larger than the sum of its proper divisors (1).

43661551 is an equidigital number, since it uses as much as digits as its factorization.

43661551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 31.

The square root of 43661551 is about 6607.6887789907. The cubic root of 43661551 is about 352.1273186772.

The spelling of 43661551 in words is "forty-three million, six hundred sixty-one thousand, five hundred fifty-one".