43394821 has 4 divisors (see below), whose sum is σ = 44567692. Its totient is φ = 42221952.

The previous prime is 43394809. The next prime is 43394831. The reversal of 43394821 is 12849334.

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 36180225 + 7214596 = 6015^2 + 2686^2 .

It is a cyclic number.

It is not a de Polignac number, because 43394821 - 2⁵ = 43394789 is a prime.

It is a super-2 number, since 2×43394821² = 3766220979244082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43394831) 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 in 3 ways as a sum of consecutive naturals, for example, 586380 + ... + 586453.

It is an arithmetic number, because the mean of its divisors is an integer number (11141923).

Almost surely, 2^43394821 is an apocalyptic number.

It is an amenable number.

43394821 is a deficient number, since it is larger than the sum of its proper divisors (1172871).

43394821 is a wasteful number, since it uses less digits than its factorization.

43394821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172870.

The product of its digits is 20736, while the sum is 34.

The square root of 43394821 is about 6587.4745540306. The cubic root of 43394821 is about 351.4088006765.

The spelling of 43394821 in words is "forty-three million, three hundred ninety-four thousand, eight hundred twenty-one".