43087921 has 2 divisors, whose sum is σ = 43087922. Its totient is φ = 43087920.

The previous prime is 43087907. The next prime is 43087931. The reversal of 43087921 is 12978034.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31798321 + 11289600 = 5639^2 + 3360^2 .

It is a cyclic number.

It is not a de Polignac number, because 43087921 - 2⁹ = 43087409 is a prime.

It is a super-2 number, since 2×43087921² = 3713137872204482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (43087931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21543960 + 21543961.

It is an arithmetic number, because the mean of its divisors is an integer number (21543961).

Almost surely, 2^43087921 is an apocalyptic number.

It is an amenable number.

43087921 is a deficient number, since it is larger than the sum of its proper divisors (1).

43087921 is an equidigital number, since it uses as much as digits as its factorization.

43087921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 43087921 is about 6564.1390143720. The cubic root of 43087921 is about 350.5784204293.

The spelling of 43087921 in words is "forty-three million, eighty-seven thousand, nine hundred twenty-one".