43750021 has 16 divisors (see below), whose sum is σ = 53017600. Its totient is φ = 35303040.

The previous prime is 43750013. The next prime is 43750033. The reversal of 43750021 is 12005734.

It is a cyclic number.

It is not a de Polignac number, because 43750021 - 2³ = 43750013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 43749974 and 43750001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43750051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5305 + ... + 10753.

It is an arithmetic number, because the mean of its divisors is an integer number (3313600).

Almost surely, 2^43750021 is an apocalyptic number.

It is an amenable number.

43750021 is a deficient number, since it is larger than the sum of its proper divisors (9267579).

43750021 is a wasteful number, since it uses less digits than its factorization.

43750021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5524.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 43750021 is about 6614.3798651121. The cubic root of 43750021 is about 352.3649929816.

Adding to 43750021 its reverse (12005734), we get a palindrome (55755755).

The spelling of 43750021 in words is "forty-three million, seven hundred fifty thousand, twenty-one".