43742821 has 4 divisors (see below), whose sum is σ = 43770700. Its totient is φ = 43714944.

The previous prime is 43742801. The next prime is 43742833. The reversal of 43742821 is 12824734.

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 19624900 + 24117921 = 4430^2 + 4911^2 .

It is a cyclic number.

It is not a de Polignac number, because 43742821 - 2¹⁹ = 43218533 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 (43742801) 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, 11436 + ... + 14773.

It is an arithmetic number, because the mean of its divisors is an integer number (10942675).

Almost surely, 2^43742821 is an apocalyptic number.

It is an amenable number.

43742821 is a deficient number, since it is larger than the sum of its proper divisors (27879).

43742821 is a wasteful number, since it uses less digits than its factorization.

43742821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27878.

The product of its digits is 10752, while the sum is 31.

The square root of 43742821 is about 6613.8355740070. The cubic root of 43742821 is about 352.3456621937.

The spelling of 43742821 in words is "forty-three million, seven hundred forty-two thousand, eight hundred twenty-one".