43501021 has 2 divisors, whose sum is σ = 43501022. Its totient is φ = 43501020.

The previous prime is 43501019. The next prime is 43501033. The reversal of 43501021 is 12010534.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40896025 + 2604996 = 6395^2 + 1614^2 .

It is a cyclic number.

It is not a de Polignac number, because 43501021 - 2¹ = 43501019 is a prime.

Together with 43501019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 43500986 and 43501004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43501001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21750510 + 21750511.

It is an arithmetic number, because the mean of its divisors is an integer number (21750511).

Almost surely, 2^43501021 is an apocalyptic number.

It is an amenable number.

43501021 is a deficient number, since it is larger than the sum of its proper divisors (1).

43501021 is an equidigital number, since it uses as much as digits as its factorization.

43501021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 43501021 is about 6595.5303804925. The cubic root of 43501021 is about 351.6952343341.

Adding to 43501021 its reverse (12010534), we get a palindrome (55511555).

The spelling of 43501021 in words is "forty-three million, five hundred one thousand, twenty-one".